The New York Subway, Its Construction and Equipment
by Interborough Rapid Transit Company · English · Gutenberg #17569 · 317,206 chars · public domain (US)
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Title: The New York Subway, Its Construction and Equipment
Author: Interborough Rapid Transit Company
Release date: January 21, 2006 [eBook #17569]
Most recently updated: December 13, 2020
Language: English
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Interborough Rapid Transit
THE NEW YORK SUBWAY
Its Construction and Equipment
[Illustration: OPERATING ROOM OF POWER HOUSE]
[Illustration: (I.R.T. symbol)]
New York
Interborough Rapid Transit Company
ANNO. DOMI. MCMIV
Copyright, 1904, by
Interborough Rapid Transit Co.
New York
Planned and Executed by The
McGraw Publishing Co.
[Illustration: (McGraw Publishing Company New York logo)]
TABLE OF CONTENTS
Page No.
INTRODUCTION, 13
CHAPTER I. THE ROUTE OF THE ROAD--PASSENGER STATIONS
AND TRACKS, 23
CHAPTER II. TYPES AND METHODS OF CONSTRUCTION, 37
CHAPTER III. POWER HOUSE BUILDING, 67
CHAPTER IV. POWER PLANT FROM COAL PILE TO SHAFTS OF
ENGINES AND TURBINES, 77
CHAPTER V. SYSTEM OF ELECTRICAL SUPPLY, 91
CHAPTER VI. ELECTRICAL EQUIPMENT OF CARS, 117
CHAPTER VII. LIGHTING SYSTEM FOR PASSENGER STATIONS
AND TUNNEL, 121
CHAPTER VIII. ROLLING STOCK--CARS, TRUCKS, ETC., 125
CHAPTER IX. SIGNAL SYSTEM, 135
CHAPTER X. SUBWAY DRAINAGE, 145
CHAPTER XI. REPAIR AND INSPECTION SHED, 147
CHAPTER XII. SUB-CONTRACTORS, 151
INTERBOROUGH RAPID TRANSIT COMPANY
_Directors_
August Belmont
E. P. Bryan
Andrew Freedman
James Jourdan
Gardiner M. Lane
John B. McDonald
Walter G. Oakman
John Peirce
Morton F. Plant
William A. Read
Alfred Skitt
Cornelius Vanderbilt
George W. Young
_Executive Committee_
August Belmont
Andrew Freedman
James Jourdan
Walter G. Oakman
William A. Read
Cornelius Vanderbilt
_Officers_
August Belmont, President
E. P. Bryan, Vice-president
H. M. Fisher, Secretary
D. W. McWilliams, Treasurer
E. F. J. Gaynor, Auditor
Frank Hedley, General Superintendent
S. L. F. Deyo, Chief Engineer
George W. Wickersham, General Counsel
Chas. A. Gardiner, General Attorney
DeLancey Nicoll, Associate Counsel
Alfred A. Gardner, Associate Counsel
_Engineering Staff_
S. L. F. Deyo, Chief Engineer.
_Electrical Equipment_
L. B. Stillwell, Electrical Director.
H. N. Latey, Principal Assistant.
Frederick R. Slater, Assistant Engineer in charge of Third Rail
Construction.
Albert F. Parks, Assistant Engineer in charge of Lighting.
George G. Raymond, Assistant Engineer in charge of Conduits and Cables.
William B. Flynn, Assistant Engineer in charge of Draughting Room.
_Mechanical and Architectural_
J. Van Vleck, Mechanical and Construction Engineer.
William C. Phelps, Assistant Construction Engineer.
William N. Stevens, Ass't Mechanical Engineer.
Paul C. Hunter, Architectural Assistant.
Geo. E. Thomas, Supervising Engineer in Field.
_Cars and Signal System_
George Gibbs, Consulting Engineer.
Watson T. Thompson, Master Mechanic.
J. N. Waldron, Signal Engineer.
RAPID TRANSIT SUBWAY CONSTRUCTION COMPANY
_Directors_
August Belmont
E. P. Bryan
Andrew Freedman
James Jourdan
Gardiner M. Lane
Walther Luttgen
John B. McDonald
Walter G. Oakman
John Peirce
Morton F. Plant
William A. Read
Cornelius Vanderbilt
George W. Young
_Executive Committee_
August Belmont
Andrew Freedman
James Jourdan
Walter G. Oakman
William A. Read
Cornelius Vanderbilt
_Officers_
August Belmont, president
Walter G. Oakman, vice-president
John B. McDonald, contractor
H. M. Fisher, secretary
John F. Buck, treasurer
E. F. J. Gaynor, auditor
S. L. F. Deyo, chief engineer
George W. Wickersham, general counsel
Alfred A. Gardner, attorney
_Engineering Staff_
S. L. F. Deyo, Chief Engineer.
H. T. Douglas, Principal Assistant Engineer.
A. Edward Olmsted, Division Engineer, Manhattan-Bronx Lines.
Henry B. Reed, Division Engineer, Brooklyn Extension.
Theodore Paschke, Resident Engineer, First Division, City Hall to 33d
Street, also Brooklyn Extension, City Hall to Bowling Green; and
Robert S. Fowler, Assistant.
Ernest C. Moore, Resident Engineer, Second Division, 33d Street to
104th Street; and Stanley Raymond, Assistant.
William C. Merryman, Resident Engineer, Third Division, Underground
Work, 104th Street to Fort George West Side and Westchester Avenue
East Side; and William B. Leonard, W. A. Morton, and William E.
Morris, Jr., Assistants.
Allan A. Robbins and Justin Burns, Resident Engineers, Fourth
Division, Viaducts; and George I. Oakley, Assistant.
Frank D. Leffingwell, Resident Engineer, East River Tunnel Division,
Brooklyn Extension; and C. D. Drew, Assistant.
Percy Litchfield, Resident Engineer, Fifth Division, Brooklyn
Extension, Borough Hall to Prospect Park; and Edward R. Eichner,
Assistant.
M. C. Hamilton, Engineer, Maintenance of Way; and Robert E. Brandeis,
Assistant.
D. L. Turner, Assistant Engineer in charge of Stations.
A. Samuel Berquist, Assistant Engineer in charge of Steel Erection.
William J. Boucher, Assistant Engineer in charge of Draughting Rooms.
[Illustration: (INTERBOROUGH RAPID TRANSIT)]
INTRODUCTION
The completion of the rapid transit railroad in the boroughs of
Manhattan and The Bronx, which is popularly known as the "Subway," has
demonstrated that underground railroads can be built beneath the
congested streets of the city, and has made possible in the near
future a comprehensive system of subsurface transportation extending
throughout the wide territory of Greater New York.
In March, 1900, when the Mayor with appropriate ceremonies broke
ground at the Borough Hall, in Manhattan, for the new road, there were
many well-informed people, including prominent financiers and
experienced engineers, who freely prophesied failure for the
enterprise, although the contract had been taken by a most capable
contractor, and one of the best known banking houses in America had
committed itself to finance the undertaking.
In looking at the finished road as a completed work, one is apt to
wonder why it ever seemed impossible and to forget the difficulties
which confronted the builders at the start.
The railway was to be owned by the city, and built and operated under
legislation unique in the history of municipal governments,
complicated, and minute in provisions for the occupation of the city
streets, payment of moneys by the city, and city supervision over
construction and operation. Questions as to the interpretation of
these provisions might have to be passed upon by the courts, with
delays, how serious none could foretell, especially in New York where
the crowded calendars retard speedy decisions. The experience of the
elevated railroad corporations in building their lines had shown the
uncertainty of depending upon legal precedents. It was not, at that
time, supposed that the abutting property owners would have any legal
ground for complaint against the elevated structures, but the courts
found new laws for new conditions and spelled out new property rights
of light, air, and access, which were made the basis for a volume of
litigation unprecedented in the courts of any country.
An underground railroad was a new condition. None could say that the
abutting property owners might not find rights substantial enough, at
least, to entitle them to their day in court, a day which, in this
State, might stretch into many months, or even several years. Owing to
the magnitude of the work, delay might easily result in failure. An
eminent judge of the New York Supreme Court had emphasized the
uncertainties of the situation in the following language: "Just what
are the rights of the owners of property abutting upon a street or
avenue, the fee in and to the soil underneath the surface of which has
been acquired by the city of New York, so far as the same is not
required for the ordinary city uses of gas or water pipes, or others
of a like character, has never been finally determined. We have now
the example of the elevated railroad, constructed and operated in the
city of New York under legislative and municipal authority for nearly
twenty years, which has been compelled to pay many millions of dollars
to abutting property owners for the easement in the public streets
appropriated by the construction and maintenance of the road, and
still the amount that the road will have to pay is not ascertained.
What liabilities will be imposed upon the city under this contract;
what injury the construction and operation of this road will cause to
abutting property, and what easements and rights will have to be
acquired before the road can be legally constructed and operated, it
is impossible now to ascertain."
It is true, that the city undertook "to secure to the contractor the
right to construct and operate, free from all rights, claims, or other
interference, whether by injunction, suit for damages, or otherwise on
the part of any abutting owner or other person." But another eminent
judge of the same court had characterized this as "a condition
absolutely impossible of fulfillment," and had said: "How is the city
to prevent interference with the work by injunction? That question
lies with the courts; and not with the courts of this State alone, for
there are cases without doubt in which the courts of the United States
would have jurisdiction to act, and when such jurisdiction exists they
have not hitherto shown much reluctance in acting.... That legal
proceedings will be undertaken which will, to some extent at least,
interfere with the progress of this work seems to be inevitable...."
Another difficulty was that the Constitution of the State of New York
limited the debt-incurring power of the city. The capacity of the city
to undertake the work had been much discussed in the courts, and the
Supreme Court of the State had disposed of that phase of the situation
by suggesting that it did not make much difference to the municipality
whether or not the debt limit permitted a contract for the work,
because if the limit should be exceeded, "no liability could possibly
be imposed upon the city," a view which might comfort the timid
taxpayers but could hardly be expected to give confidence to the
capitalists who might undertake the execution of the contract.
Various corporations, organized during the thirty odd years of
unsuccessful attempts by the city to secure underground rapid transit,
claimed that their franchises gave them vested rights in the streets
to the exclusion of the new enterprise, and they were prepared to
assert their rights in the courts. (The Underground Railroad Company
of the City of New York sought to enjoin the building of the road and
carried their contest to the Supreme Court of the United States which
did not finally decide the questions raised until March, 1904, when
the subway was practically complete.)
Rival transportation companies stood ready to obstruct the work and
encourage whomever might find objection to the building of the road.
New York has biennial elections. The road could not be completed in
two years, and the attitude of one administration might not be the
attitude of its successors.
The engineering difficulties were well-nigh appalling. Towering
buildings along the streets had to be considered, and the streets
themselves were already occupied with a complicated network of
subsurface structures, such as sewers, water and gas mains, electric
cable conduits, electric surface railway conduits, telegraph and
power conduits, and many vaults extending out under the streets,
occupied by the abutting property owners. On the surface were street
railway lines carrying a very heavy traffic night and day, and all the
thoroughfares in the lower part of the city were congested with
vehicular traffic.
Finally, the city was unwilling to take any risk, and demanded
millions of dollars of security to insure the completion of the road
according to the contract, the terms of which were most exacting down
to the smallest detail.
The builders of the road did not underestimate the magnitude of the
task before them. They retained the most experienced experts for every
part of the work and, perfecting an organization in an incredibly
short time, proceeded to surmount and sweep aside difficulties. The
result is one of which every citizen of New York may feel proud. Upon
the completion of the road the city will own the best constructed and
best equipped intraurban rapid transit railroad in the world. The
efforts of the builders have not been limited by the strict terms of
the contract. They have striven, not to equal the best devices, but to
improve upon the best devices used in modern electrical railroading,
to secure for the traveling public safety, comfort, and speedy
transportation.
The road is off the surface and escapes the delays incident to
congested city streets, but near the surface and accessible, light,
dry, clean, and well ventilated. The stations and approaches are
commodious, and the stations themselves furnish conveniences to
passengers heretofore not heard of on intraurban lines. There is a
separate express service, with its own tracks, and the stations are so
arranged that passengers may pass from local trains to express trains,
and vice versa, without delay and without payment of additional fare.
Special precautions have been taken and devices adopted to prevent a
failure of the electric power and the consequent delays of traffic. An
electro pneumatic block signal system has been devised, which excels
any system heretofore used and is unique in its mechanism. The third
rail for conveying the electric current is covered, so as to prevent
injury to passengers and employees from contact. Special emergency and
fire alarm signal systems are installed throughout the length of the
road. At a few stations, where the road is not near the surface,
improved escalators and elevators are provided. The cars have been
designed to prevent danger from fire, and improved types of motors
have been adopted, capable of supplying great speed combined with
complete control. Strength, utility, and convenience have not alone
been considered, but all parts of the railroad structures and
equipment, stations, power house, and electrical sub-stations have
been designed and constructed with a view to the beauty of their
appearance, as well as to their efficiency.
The completion of the subway marks the solution of a problem which for
over thirty years baffled the people of New York City, in spite of the
best efforts of many of its foremost citizens. An extended account of
Rapid Transit Legislation would be out of place here, but a brief
glance at the history of the Act under the authority of which the
subway has been built is necessary to a clear understanding of the
work which has been accomplished. From 1850 to 1865 the street surface
horse railways were sufficient for the requirements of the traveling
public. As the city grew rapidly, the congestion spreading northward,
to and beyond the Harlem River, the service of surface roads became
entirely inadequate. As early as 1868, forty-two well known business
men of the city became, by special legislative Act, incorporators of
the New York City Central Underground Railway Company, to build a line
from the City Hall to the Harlem River. The names of the incorporators
evidenced the seriousness of the attempt, but nothing came of it. In
1872, also by special Act, Cornelius Vanderbilt and others were
incorporated as The New York City Rapid Transit Company, to build an
underground road from the City Hall to connect with the New York &
Harlem Road at 59th Street, with a branch to the tracks of the New
York Central Road. The enterprise was soon abandoned. Numerous
companies were incorporated in the succeeding years under the general
railroad laws, to build underground roads, but without results; among
them the Central Tunnel Railway Company in 1881, The New York & New
Jersey Tunnel Railway Company in 1883, The Terminal Underground
Railway Company in 1886, The Underground Railroad Company of the City
of New York (a consolidation of the last two companies) in 1896, and
The Rapid Transit Underground Railroad Company in 1897.
All attempts to build a road under the early special charter and later
under the general laws having failed, the city secured in 1891 the
passage of the Rapid Transit Act under which, as amended, the subway
has been built. As originally passed it did not provide for municipal
ownership. It provided that a board of five rapid transit railroad
commissioners might adopt routes and general plans for a railroad,
obtain the consents of the local authorities and abutting property
owners, or in lieu of the consents of the property owners the approval
of the Supreme Court; and then, having adopted detail plans for the
construction and operation, might sell at public sale the right to
build and operate the road to a corporation, whose powers and duties
were defined in the Act, for such period of time and on such terms as
they could. The Commissioners prepared plans and obtained the consents
of the local authorities. The property owners refused their consent;
the Supreme Court gave its approval in lieu thereof, but upon inviting
bids the Board of Rapid Transit Railroad Commissioners found no
responsible bidder.
The late Hon. Abram S. Hewitt, as early as 1884, when legislation for
underground roads was under discussion, had urged municipal ownership.
Speaking in 1901, he said of his efforts in 1884:
"It was evident to me that underground rapid transit could
not be secured by the investment of private capital, but in
some way or other its construction was dependent upon the
use of the credit of the City of New York. It was also
apparent to me that if such credit were used, the property
must belong to the city. Inasmuch as it would not be safe
for the city to undertake the construction itself, the
intervention of a contracting company appeared
indispensable. To secure the city against loss, this company
must necessarily be required to give a sufficient bond for
the completion of the work and be willing to enter into a
contract for its continued operation under a rental which
would pay the interest upon the bonds issued by the city for
the construction, and provide a sinking fund sufficient for
the payment of the bonds at or before maturity. It also
seemed to be indispensable that the leasing company should
invest in the rolling stock and in the real estate required
for its power houses and other buildings an amount of money
sufficiently large to indemnify the city against loss in
case the lessees should fail in their undertaking to build
and operate the railroad."
Mr. Hewitt became Mayor of the city in 1887, and his views were
presented in the form of a Bill to the Legislature in the following
year. The measure found practically no support. Six years later, after
the Rapid Transit Commissioners had failed under the Act of 1891, as
originally drawn, to obtain bidders for the franchise, the New York
Chamber of Commerce undertook to solve the problem by reverting to Mr.
Hewitt's idea of municipal ownership. Whether or not municipal
ownership would meet the approval of the citizens of New York could
not be determined; therefore, as a preliminary step, it was decided to
submit the question to a popular vote. An amendment to the Act of 1891
was drawn (Chapter 752 of the Laws of 1894) which provided that the
qualified electors of the city were to decide at an annual election,
by ballot, whether the rapid transit railway or railways should be
constructed by the city and at the public's expense, and be operated
under lease from the city, or should be constructed by a private
corporation under a franchise to be sold in the manner attempted
unsuccessfully, under the Act of 1891, as originally passed. At the
fall election of 1894, the electors of the city, by a very large vote,
declared against the sale of a franchise to a private corporation and
in favor of ownership by the city. Several other amendments, the
necessity for which developed as plans for the railway were worked
out, were made up to and including the session of the Legislature of
1900, but the general scheme for rapid transit may be said to have
become fixed when the electors declared in favor of municipal
ownership. The main provisions of the legislation which stood upon the
statute books as the Rapid Transit Act, when the contract was finally
executed, February 21, 1900, may be briefly summarized as follows:
(_a_) The Act was general in terms, applying to all cities in the
State having a population of over one million; it was special in
effect because New York was the only city having such a population. It
did not limit the Rapid Transit Commissioners to the building of a
single road, but authorized the laying out of successive roads or
extensions.
(_b_) A Board was created consisting of the Mayor, Comptroller, or
other chief financial officer of the city; the president of the
Chamber of Commerce of the State of New York, by virtue of his office,
and five members named in the Act: William Steinway, Seth Low, John
Claflin, Alexander E. Orr, and John H. Starin, men distinguished for
their business experience, high integrity, and civic pride. Vacancies
in the Board were to be filled by the Board itself, a guaranty of a
continued uniform policy.
(_c_) The Board was to prepare general routes and plans and submit the
question of municipal ownership to the electors of the city.
(_d_) The city was authorized, in the event that the electors decided
for city ownership, to issue bonds not to exceed $50,000,000 for the
construction of the road or roads and $5,000,000 additional, if
necessary, for acquiring property rights for the route. The interest
on the bonds was not to exceed 3-1/2 per cent.
(_e_) The Commissioners were given the broad power to enter into a
contract (in the case of more than one road, successive contracts) on
behalf of the city for the construction of the road with the person,
firm, or corporation which in the opinion of the Board should be best
qualified to carry out the contract, and to determine the amount of
the bond to be given by the contractor to secure its performance. The
essential features of the contract were, however, prescribed by the
Act. The contractor in and by the contract for building the road was
to agree to fully equip it at his own expense, and the equipment was
to include all power houses. He was also to operate the road, as
lessee of the city, for a term not to exceed fifty years, upon terms
to be included in the contract for construction, which might include
provision for renewals of the lease upon such terms as the Board
should from time to time determine. The rental was to be at least
equal to the amount of interest on the bonds which the city might
issue for construction and one per cent. additional. The one per cent.
additional might, in the discretion of the Board, be made contingent
in part for the first ten years of the lease upon the earnings of the
road. The rental was to be applied by the city to the interest on the
bonds and the balance was to be paid into the city's general sinking
fund for payment of the city's debt or into a sinking fund for the
redemption at maturity of the bonds issued for the construction of the
rapid transit road, or roads. In addition to the security which might
be required by the Board of the contractor for construction and
operation, the Act provided that the city should have a first lien
upon the equipment of the road to be furnished by the contractor, and
at the termination of the lease the city had the privilege of
purchasing such equipment from the contractor.
(_f_) The city was to furnish the right of way to the contractor free
from all claims of abutting property owners. The road was to be the
absolute property of the city and to be deemed a part of the public
streets and highways. The equipment of the road was to be exempt from
taxation.
(_g_) The Board was authorized to include in the contract for
construction provisions in detail for the supervision of the city,
through the Board, over the operation of the road under the lease.
One of the most attractive--and, in fact, indispensable features of
the scheme--was that the work of construction, instead of being
subject to the conflicting control of various departments of the City
Government, with their frequent changes in personnel, was under the
exclusive supervision and control of the Rapid Transit Board, a
conservative and continuous body composed of the two principal
officers of the City Government, and five merchants of the very
highest standing in the community.
Provided capitalists could be found to undertake such an extensive
work under the exacting provisions, the scheme was an admirable one
from the taxpayers' point of view. The road would cost the city
practically nothing and the obligation of the contractor to equip and
operate being combined with the agreement to construct furnished a
safeguard against waste of the public funds and insured the prompt
completion of the road. The interest of the contractor in the
successful operation, after construction, furnished a strong incentive
to see that as the construction progressed the details were consistent
with successful operation and to suggest and consent to such
modifications of the contract plans as might appear necessary from an
operating point of view, from time to time. The rental being based
upon the cost encouraged low bids, and the lien of the city upon the
equipment secured the city against all risk, once the road was in
operation.
Immediately after the vote of the electors upon the question of
municipal ownership, the Rapid Transit Commissioners adopted routes
and plans which they had been studying and perfecting since the
failure to find bidders for the franchise under the original Act of
1891. The local authorities approved them, and again the property
owners refused their consent, making an application to the Supreme
Court necessary. The Court refused its approval upon the ground that
the city, owing to a provision of the constitution of the State
limiting the city's power to incur debt, would be unable to raise the
necessary money. This decision appeared to nullify all the efforts of
the public spirited citizens composing the Board of Rapid Transit
Commissioners and to practically prohibit further attempts on their
part. They persevered, however, and in January, 1897, adopted new
general routes and plans. The consolidation of a large territory into
the Greater New York, and increased land values, warranted the hope
that the city's debt limit would no longer be an objection, especially
as the new route changed the line so as to reduce the estimated cost.
The demands for rapid transit had become more and more imperative as
the years went by, and it was fair to assume that neither the courts
nor the municipal authorities would be overzealous to find a narrow
construction of the laws. Incidentally, the constitutionality of the
rapid transit legislation, in its fundamental features, had been
upheld in the Supreme Court in a decision which was affirmed by the
highest court of the State a few weeks after the Board had adopted its
new plans. The local authorities gave their consent to the new route;
the property owners, as on the two previous occasions, refused their
consent; the Supreme Court gave its approval in lieu thereof; and the
Board was prepared to undertake the preliminaries for letting a
contract. These successive steps and the preparation of the terms of
the contract all took time; but, finally, on November 15, 1899, a form
of contract was adopted and an invitation issued by the Board to
contractors to bid for the construction and operation of the railroad.
There were two bidders, one of whom was John B. McDonald, whose terms
submitted under the invitation were accepted on January 15, 1900; and,
for the first time, it seemed as if a beginning might be made in the
actual construction of the rapid transit road. The letter of
invitation to contractors required that every proposal should be
accompanied by a certified check upon a National or State Bank,
payable to the order of the Comptroller, for $150,000, and that within
ten days after acceptance, or within such further period as might be
prescribed by the Board, the contract should be duly executed and
delivered. The amount to be paid by the city for the construction was
$35,000,000 and an additional sum not to exceed $2,750,000 for
terminals, station sites, and other purposes. The construction was to
be completed in four years and a half, and the term of the lease from
the city to the contractor was fixed at fifty years, with a renewal,
at the option of the contractor, for twenty-five years at a rental to
be agreed upon by the city, not less than the average rental for the
then preceding ten years. The rental for the fifty-year term was fixed
at an amount equal to the annual interest upon the bonds issued by the
city for construction and 1 per cent. additional, such 1 per cent.
during the first ten years to be contingent in part upon the earnings
of the road. To secure the performance of the contract by Mr. McDonald
the city required him to deposit $1,000,000 in cash as security for
construction, to furnish a bond with surety for $5,000,000 as security
for construction and equipment, and to furnish another bond of
$1,000,000 as continuing security for the performance of the contract.
The city in addition to this security had, under the provisions of the
Rapid Transit Act, a first lien on the equipment, and it should be
mentioned that at the expiration of the lease and renewals (if any)
the equipment is to be turned over to the city, pending an agreement
or arbitration upon the question of the price to be paid for it by the
city. The contract (which covered about 200 printed pages) was minute
in detail as to the work to be done, and sweeping powers of
supervision were given the city through the Chief Engineer of the
Board, who by the contract was made arbiter of all questions that
might arise as to the interpretation of the plans and specifications.
The city had been fortunate in securing for the preparation of plans
the services of Mr. William Barclay Parsons, one of the foremost
engineers of the country. For years as Chief Engineer of the Board he
had studied and developed the various plans and it was he who was to
superintend on behalf of the city the completion of the work.
During the thirty-two years of rapid transit discussion between 1868,
when the New York City Central Underground Company was incorporated,
up to 1900, when the invitations for bids were issued by the city,
every scheme for rapid transit had failed because responsible
capitalists could not be found willing to undertake the task of
building a road. Each year had increased the difficulties attending
such an enterprise and the scheme finally evolved had put all of the
risk upon the capitalists who might attempt to finance the work, and
left none upon the city. Without detracting from the credit due the
public-spirited citizens who had evolved the plan of municipal
ownership, it may be safely asserted that the success of the
undertaking depended almost entirely upon the financial backing of the
contractor. When the bid was accepted by the city no arrangements had
been made for the capital necessary to carry out the contract. After
its acceptance, Mr. McDonald not only found little encouragement in
his efforts to secure the capital, but discovered that the surety
companies were unwilling to furnish the security required of him,
except on terms impossible for him to fulfill.
The crucial point in the whole problem of rapid transit with which the
citizens of New York had struggled for so many years had been reached,
and failure seemed inevitable. The requirements of the Rapid Transit
Act were rigid and forbade any solution of the problem which committed
the city to share in the risks of the undertaking. Engineers might
make routes and plans, lawyers might draw legislative acts, the city
might prepare contracts, the question was and always had been, Can
anybody build the road who will agree to do it and hold the city safe
from loss?
It was obvious when the surety companies declined the issue that the
whole rapid transit problem was thrown open, or rather that it always
had been open. The final analysis had not been made. After all, the
attitude of the surety companies was only a reflection of the general
feeling of practical business and railroad men towards the whole
venture. To the companies the proposition had come as a concrete
business proffer and they had rejected it.
At this critical point, Mr. McDonald sought the assistance of Mr.
August Belmont. It was left to Mr. Belmont to make the final analysis,
and avert the failure which impended. There was no time for indecision
or delay. Whatever was to be done must be done immediately. The
necessary capital must be procured, the required security must be
given, and an organization for building and operating the road must be
anticipated. Mr. Belmont looking through and beyond the intricacies of
the Rapid Transit Act, and the complications of the contract, saw that
he who undertook to surmount the difficulties presented by the
attitude of the surety companies must solve the whole problem. It was
not the ordinary question of financing a railroad contract. He saw
that the responsibility for the entire rapid transit undertaking must
be centered, and that a compact and effective organization must be
planned which could deal with every phase of the situation.
Mr. Belmont without delay took the matter up directly with the Board
of Rapid Transit Railroad Commissioners, and presented a plan for the
incorporation of a company to procure the security required for the
performance of the contract, to furnish the capital necessary to carry
on the work, and to assume supervision over the whole undertaking.
Application was to be made to the Supreme Court to modify the
requirements with respect to the sureties by striking out a provision
requiring the justification of the sureties in double the amount of
liabilities assumed by each and reducing the minimum amount permitted
to be taken by each surety from $500,000 to $250,000. The new
corporation was to execute as surety a bond for $4,000,000, the
additional amount of $1,000,000 to be furnished by other sureties. A
beneficial interest in the bonds required from the sub-contractors was
to be assigned to the city and, finally, the additional amount of
$1,000,000, in cash or securities, was to be deposited with the city
as further security for the performance of the contract. The plan was
approved by the Board of Rapid Transit Railroad Commissioners, and
pursuant to the plan, the Rapid Transit Subway Construction Company
was organized. The Supreme Court granted the application to modify the
requirements as to the justification of sureties and the contract was
executed February 21, 1900.
As president and active executive head of the Rapid Transit Subway
Construction Company, Mr. Belmont perfected its organization,
collected the staff of engineers under whose direction the work of
building the road was to be done, supervised the letting of
sub-contracts, and completed the financial arrangements for carrying
on the work.
The equipment of the road included, under the terms of the contract,
the rolling stock, all machinery and mechanisms for generating
electricity for motive power, lighting, and signaling, and also the
power house, sub-stations, and the real estate upon which they were to
be erected. The magnitude of the task of providing the equipment was
not generally appreciated until Mr. Belmont took the rapid transit
problem in hand. He foresaw from the beginning the importance of that
branch of the work, and early in 1900, immediately after the signing
of the contract, turned his attention to selecting the best engineers
and operating experts, and planned the organization of an operating
company. As early as May, 1900, he secured the services of Mr. E. P.
Bryan, who came to New York from St. Louis, resigning as
vice-president and general manager of the Terminal Railroad
Association, and began a study of the construction work and plans for
equipment, to the end that the problems of operation might be
anticipated as the building and equipment of the road progressed. Upon
the incorporation of the operating company, Mr. Bryan became
vice-president.
In the spring of 1902, the Interborough Rapid Transit Company, the
operating railroad corporation was formed by the interests represented
by Mr. Belmont, he becoming president and active executive head of
this company also, and soon thereafter Mr. McDonald assigned to it the
lease or operating part of his contract with the city, that company
thereby becoming directly responsible to the city for the equipment
and operation of the road, Mr. McDonald remaining as contractor for
its construction. In the summer of the same year, the Board of Rapid
Transit Railroad Commissioners having adopted a route and plans for an
extension of the subway under the East River to the Borough of
Brooklyn, the Rapid Transit Subway Construction Company entered into a
contract with the city, similar in form to Mr. McDonald's contract, to
build, equip, and operate the extension. Mr. McDonald, as contractor
of the Rapid Transit Subway Construction Company, assumed the general
supervision of the work of constructing the Brooklyn extension; and
the construction work of both the original subway and the extension
has been carried on under his direction. The work of construction has
been greatly facilitated by the broad minded and liberal policy of the
Rapid Transit Board and its Chief Engineer and Counsel, and by the
coöperation of all the other departments of the City Government, and
also by the generous attitude of the Metropolitan Street Railway
Company and its lessee, the New York City Railroad Company, in
extending privileges which have been of great assistance in the
prosecution of the work. In January, 1903, the Interborough Rapid
Transit Company acquired the elevated railway system by lease for 999
years from the Manhattan Railway Company, thus assuring harmonious
operation of the elevated roads and the subway system, including the
Brooklyn extension.
The incorporators of the Interborough Rapid Transit Company were
William H. Baldwin, Jr., Charles T. Barney, August Belmont, E. P.
Bryan, Andrew Freedman, James Jourdan, Gardiner M. Lane, John B.
McDonald, DeLancey Nicoll, Walter G. Oakman, John Peirce, Wm. A. Read,
Cornelius Vanderbilt, George W. Wickersham, and George W. Young.
The incorporators of the Rapid Transit Subway Construction Company
were Charles T. Barney, August Belmont, John B. McDonald, Walter G.
Oakman, and William A. Read.
[Illustration: (wings)]
[Illustration: EXTERIOR VIEW OF POWER HOUSE]
CHAPTER I
THE ROUTE OF THE ROAD--PASSENGER STATIONS AND TRACKS
The selection of route for the Subway was governed largely by the
amount which the city was authorized by the Rapid Transit Act to
spend. The main object of the road was to carry to and from their
homes in the upper portions of Manhattan Island the great army of
workers who spend the business day in the offices, shops, and
warehouses of the lower portions, and it was therefore obvious that
the general direction of the routes must be north and south, and that
the line must extend as nearly as possible from one end of the island
to the other.
The routes proposed by the Rapid Transit Board in 1895, after
municipal ownership had been approved by the voters at the fall
election of 1894, contemplated the occupation of Broadway below 34th
Street to the Battery, and extended only to 185th Street on the west
side and 146th Street on the east side of the city. As has been told
in the introductory chapter, this plan was rejected by the Supreme
Court because of the probable cost of going under Broadway. It was
also intimated by the Court, in rejecting the routes, that the road
should extend further north.
It had been clear from the beginning that no routes could be laid out
to which abutting property owners would consent, and that the consent
of the Court as an alternative would be necessary to any routes
chosen. To conform as nearly as possible to the views of the Court,
the Commission proposed, in 1897, the so called "Elm Street route,"
the plan finally adopted, which reached from the territory near the
General Post-office, the City Hall, and Brooklyn Bridge Terminal to
Kingsbridge and the station of the New York & Putnam Railroad on the
upper west side, and to Bronx Park on the upper east side of the city,
touching the Grand Central Depot at 42d Street.
Subsequently, by the adoption of the Brooklyn Extension, the line was
extended down Broadway to the southern extremity of Manhattan Island,
thence under the East River to Brooklyn.
The routes in detail are as follows:
[Sidenote:
_Manhattan-Bronx
Route_]
Beginning near the intersection of Broadway and Park Row, one of the
routes of the railroad extends under Park Row, Center Street, New Elm
Street, Elm Street, Lafayette Place, Fourth Avenue (beginning at Astor
Place), Park Avenue, 42d Street, and Broadway to 125th Street, where
it passes over Broadway by viaduct to 133d Street, thence under
Broadway again to and under Eleventh Avenue to Fort George, where it
comes to the surface again at Dyckman Street and continues by viaduct
over Naegle Avenue, Amsterdam Avenue, and Broadway to Bailey Avenue,
at the Kingsbridge station of the New York & Putnam Railroad, crossing
the Harlem Ship Canal on a double-deck drawbridge. The length of this
route is 13.50 miles, of which about 2 miles are on viaduct.
Another route begins at Broadway near 103d Street and extends under
104th Street and the upper part of Central Park to and under Lenox
Avenue to 142d Street, thence curving to the east to and under the
Harlem River at about 145th Street, thence from the river to and
under East 149th Street to a point near Third Avenue, thence by
viaduct beginning at Brook Avenue over Westchester Avenue, the
Southern Boulevard and the Boston Road to Bronx Park. The length of
this route is about 6.97 miles, of which about 3 miles are on viaduct.
[Illustration: MAP SHOWING THE LINES OF THE INTERBOROUGH RAPID TRANSIT
CO. 1904]
At the City Hall there is a loop under the Park. From 142d Street
there is a spur north under Lenox Avenue to 148th Street. There is a
spur at Westchester and Third Avenues connecting by viaduct the
Manhattan Elevated Railway Division of Interborough Rapid Transit
Company with the viaduct of the subway at or near St. Ann's Avenue.
[Sidenote: _Brooklyn Route_]
The route of the Brooklyn Extension connects near Broadway and Park
Row with the Manhattan Bronx Route and extends under Broadway, Bowling
Green, State Street, Battery Park, Whitehall Street, and South Street
to and under the East River to Brooklyn at the foot of Joralemon
Street, thence under Joralemon Street, Fulton Street, and Flatbush
Avenue to Atlantic Avenue, connecting with the Brooklyn tunnel of the
Long Island Railroad at that point. There is a loop under Battery Park
beginning at Bridge Street. The length of this route is about 3 miles.
The routes in Manhattan and The Bronx may therefore be said to roughly
resemble the letter Y with the base at the southern extremity of
Manhattan Island, the fork at 103d Street and Broadway, the terminus
of the westerly or Fort George branch of the fork just beyond Spuyten
Duyvil Creek, the terminus of the easterly or Bronx Park branch at
Bronx Park.
[Sidenote: _Location
of Stations_]
The stations beginning at the base of the Y and following the route up
to the fork are located at the following points:
South Ferry, Bowling Green and Battery Place, Rector Street and
Broadway, Fulton Street and Broadway, City Hall, Manhattan; Brooklyn
Bridge Entrance, Manhattan; Worth and Elm Streets, Canal and Elm
Streets, Spring and Elm Streets, Bleecker and Elm Streets, Astor Place
and Fourth Avenue, 14th Street and Fourth Avenue, 18th Street and
Fourth Avenue, 23d Street and Fourth Avenue, 28th Street and Fourth
Avenue, 33d Street and Fourth Avenue, 42d Street and Madison Avenue
(Grand Central Station), 42d Street and Broadway, 50th Street and
Broadway, 60th Street and Broadway (Columbus Circle), 66th Street and
Broadway, 72d Street and Broadway, 79th Street and Broadway, 86th
Street and Broadway, 91st Street and Broadway, 96th Street and
Broadway.
[Illustration: 34TH STREET AND PARK AVENUE, LOOKING SOUTH]
The stations of the Fort George or westerly branch are located at the
following points:
One Hundred and Third Street and Broadway, 110th Street and Broadway
(Cathedral Parkway), 116th Street and Broadway (Columbia University),
Manhattan Street (near 128th Street) and Broadway, 137th Street and
Broadway, 145th Street and Broadway, 157th Street and Broadway, the
intersection of 168th Street, St. Nicholas Avenue and Broadway, 181st
Street and Eleventh Avenue, Dyckman Street and Naegle Avenue (beyond
Fort George), 207th Street and Amsterdam Avenue, 215th Street and
Amsterdam Avenue, Muscoota Street and Broadway, Bailey Avenue, at
Kingsbridge near the New York & Putnam Railroad station.
The stations on the Bronx Park or easterly branch are located at the
following points:
One Hundred and Tenth Street and Lenox Avenue, 116th Street and Lenox
Avenue, 125th Street and Lenox Avenue, 135th Street and Lenox Avenue,
145th Street and Lenox Avenue (spur), Mott Avenue and 149th Street,
the intersection of 149th Street, Melrose and Third Avenues, Jackson
and Westchester Avenues, Prospect and Westchester Avenues, Westchester
Avenue near Southern Boulevard (Fox Street), Freeman Street and the
Southern Boulevard, intersection of 174th Street, Southern Boulevard
and Boston Road, 177th Street and Boston Road (near Bronx Park).
[Illustration: PROFILE OF RAPID TRANSIT RAILROAD MANHATTAN AND
BRONX LINES.]
The stations in the Borough of Brooklyn on the Brooklyn Extension are
located as follows:
Joralemon Street near Court (Brooklyn Borough Hall), intersection of
Fulton, Bridge, and Hoyt Streets; Flatbush Avenue near Nevins Street,
Atlantic Avenue and Flatbush Avenue (Brooklyn terminal of the Long
Island Railroad).
From the Borough Hall, Manhattan, to the 96th Street station, the line
is four-track. On the Fort George branch (including 103d Street
station) there are three tracks to 145th Street and then two tracks to
Dyckman Street, then three tracks again to the terminus at Bailey
Avenue. On the Bronx Park branch there are two tracks to Brook Avenue
and from that point to Bronx Park there are three tracks. On the Lenox
Avenue spur to 148th Street there are two tracks, on the City Hall
loop one track, on the Battery Park loop two tracks. The Brooklyn
Extension is a two-track line.
There is a storage yard under Broadway between 137th Street and 145th
Street on the Fort George branch, another on the surface at the end of
the Lenox Avenue spur, Lenox Avenue and 148th Street, and a third on
an elevated structure at the Boston Road and 178th Street. There is a
repair shop and inspection shed on the surface adjoining the Lenox
Avenue spur at the Harlem River and 148-150th Streets, and an
inspection shed at the storage yard at Boston Road and 178th Street.
[Sidenote: _Length of
Line._]
The total length of the line from the City Hall to the Kingsbridge
terminal is 13.50 miles, with 47.11 miles of single track and sidings.
The eastern or Bronx Park branch is 6.97 miles long, with 17.50 miles
of single track.
[Illustration: PROFILE OF BROOKLYN EXTENSION.]
[Sidenote: _Grades and
Curves._]
The total length of the Brooklyn Extension is 3.1 miles, with about 8
miles of single track.
The grades and curvature along the main line may be summarized as
follows:
The total curvature is equal in length to 23 per cent. of the straight
line, and the least radius of curvature is 147 feet. The greatest
grade is 3 per cent., and occurs on either side of the tunnel under
the Harlem River. At each station there is a down grade of 2.1 per
cent., to assist in the acceleration of the cars when they start. In
order to make time on roads running trains at frequent intervals, it
is necessary to bring the trains to their full speed very soon after
starting. The electrical equipment of the Rapid Transit Railroad will
enable this to be done in a better manner than is possible with steam
locomotives, while these short acceleration grades at each station, on
both up and down tracks, will be of material assistance in making the
starts smooth.
Photograph on page 26 shows an interesting feature at a local
station, where, in order to obtain the quick acceleration in grade for
local trains, and at the same time maintain a level grade for the
express service, the tracks are constructed at a different level. This
occurs at many local stations.
On the Brooklyn Extension the maximum grade is 3.1 per cent.
descending from the ends to the center of the East River tunnel. The
minimum radius of curve is 1,200 feet.
[Illustration: STANDARD STEEL CONSTRUCTION IN TUNNEL--THIRD RAIL
PROTECTION NOT SHOWN]
[Illustration: PLAN OF BROOKLYN BRIDGE STATION AND CITY HALL LOOP]
[Sidenote: _Track_]
The track is of the usual standard construction with broken stone
ballast, timber cross ties, and 100-pound rails of the American
Society of Civil Engineers' section. The cross ties are selected hard
pine. All ties are fitted with tie plates. All curves are supplied
with steel inside guard rails. The frogs and switches are of the best
design and quality to be had, and a special design has been used on
all curves. At the Battery loop, at Westchester Avenue, at 96th
Street, and at City Hall loop, where it has been necessary for the
regular passenger tracks to cross, grade crossings have been avoided;
one track or set of tracks passing under the other at the intersecting
points. (See plan on this page.)
The contract for the building of the road contains the following
somewhat unusual provision: "The railway and its equipment as
contemplated by the contract constitute a great public work. All parts
of the structure where exposed to public sight shall therefore be
designed, constructed, and maintained with a view to the beauty of
their appearance, as well as to their efficiency."
It may be said with exact truthfulness that the builders have spared
no effort or expense to live up to the spirit of this provision, and
that all parts of the road and equipment display dignified and
consistent artistic effects of the highest order. These are noticeable
in the power house and the electrical sub-stations and particularly in
the passenger stations. It might readily have been supposed that the
limited space and comparative uniformity of the underground stations
would afford but little opportunity for architectural and decorative
effects. The result has shown the fallacy of such a supposition.
[Illustration: PLAN OF 28TH ST. & 4TH AVENUE STATION.]
Of the forty-eight stations, thirty-three are underground, eleven are
on the viaduct portions of the road, and three are partly on the
surface and partly underground, and one is partly on the surface and
partly on the viaduct.
[Sidenote: _Space Occupied_]
The underground stations are at the street intersections, and, except
in a few instances, occupy space under the cross streets. The station
plans are necessarily varied to suit the conditions of the different
locations, the most important factor in planning them having been the
amount of available space. The platforms are from 200 to 350 feet in
length, and about 16 feet in width, narrowing at the ends, while the
center space is larger or smaller, according to local conditions. As a
rule the body of the station extends back about 50 feet from the edge
of the platform.
At all local stations (except at 110th Street and Lenox Avenue) the
platforms are outside of the tracks. (Plan and photograph on pages
30 and 31.) At Lenox Avenue and 110th Street there is a single island
platform for uptown and downtown passengers.
[Illustration: 28TH STREET STATION]
[Sidenote: _Island
Platforms_]
At express stations there are two island platforms between the express
and local tracks, one for uptown and one for downtown traffic. In
addition, there are the usual local platforms at Brooklyn Bridge, 14th
Street (photograph on page 34) and 96th Street. At the remaining
express stations, 42d Street and Madison Avenue and 72d Street, there
are no local platforms outside of the tracks, local and through
traffic using the island platforms.
The island platforms at Brooklyn Bridge, 14th Street, and 42d Street
and Madison Avenue are reached by mezzanine footways from the local
platforms, it having been impossible to place entrances in the streets
immediately over the platforms. At 96th Street there is an underground
passage connecting the local and island platforms, and at 72d Street
there are entrances to the island platforms directly from the street
because there is a park area in the middle of the street. Local
passengers can transfer from express trains and express passengers
from local trains without payment of additional fare by stepping
across the island platforms.
At 72d Street, at 103d Street, and at 116th Street and Broadway the
station platforms are below the surface, but the ticket booths and
toilet rooms are on the surface; this arrangement being possible also
because of the park area available in the streets. At Manhattan Street
the platforms are on the viaduct, but the ticket booths and toilet
rooms are on the surface. The viaduct at this point is about 68 feet
above the surface, and escalators are provided. At many of the
stations entrances have been arranged from the adjacent buildings, in
addition to the entrances originally planned from the street.
[Sidenote: Kiosks]
The entrances to the underground stations are enclosed at the street
by kiosks of cast iron and wire glass (photograph on page 33), and
vary in number from two to eight at a station. The stairways are of
concrete, reinforced by twisted steel rods. At 168th Street, at 181st
Street, and at Mott Avenue, where the platforms are from 90 to 100
feet below the surface, elevators are provided.
[Illustration: WEST SIDE OF 23D STREET STATION]
At twenty of the underground stations it has been possible to use
vault lights to such an extent that very little artificial light is
needed. (Photograph on page 35.) Such artificial light as is
required is supplied by incandescent lamps sunk in the ceilings.
Provision has been made for using the track circuit for lighting in
emergency if the regular lighting circuit should temporarily fail.
[Illustration: KIOSKS AT COLUMBUS CIRCLE]
The station floors are of concrete, marked off in squares. At the
junction of the floors and side walls a cement sanitary cove is
placed. The floors drain to catch-basins, and hose bibs are provided
for washing the floors.
[Illustration: BROOKLYN BRIDGE STATION]
Two types of ceiling are used, one flat, which covers the steel and
concrete of the roof, and the other arched between the roof beams and
girders, the lower flanges of which are exposed. Both types have an
air space between ceiling and roof, which, together with the air
space behind the inner side walls, permits air to circulate and
minimizes condensation on the surface of the ceiling and walls.
[Illustration: PLAQUE SHOWING BEAVER AT ASTOR PLACE STATION]
The ceilings are separated into panels by wide ornamental mouldings,
and the panels are decorated with narrower mouldings and rosettes. The
bases of the walls are buff Norman brick. Above this is glass tile or
glazed tile, and above the tile is a faience or terra-cotta cornice.
Ceramic mosaic is used for decorative panels, friezes, pilasters, and
name-tablets. A different decorative treatment is used at each
station, including a distinctive color scheme. At some stations the
number of the intersecting street or initial letter of the street name
is shown on conspicuous plaques, at other stations the number or
letter is in the panel. At some stations artistic emblems have been
used in the scheme of decoration, as at Astor Place, the beaver (see
photograph on this page); at Columbus Circle, the great
navigator's Caravel; at 116th Street, the seal of Columbia University.
The walls above the cornice and the ceilings are finished in white
Keene cement.
[Illustration: EXPRESS STATION AT 14TH STREET, SHOWING ISLAND AND
MEZZANINE PLATFORMS AND STAIRS CONNECTING THEM]
[Illustration: WEST SIDE OF COLUMBUS CIRCLE STATION (60TH
STREET)--ILLUMINATED BY DAYLIGHT COMING THROUGH VAULT LIGHTS]
[Illustration: CARAVEL AND WALL DECORATION]
The ticket booths are of oak with bronze window grills and fittings.
There are toilet rooms in every station, except at the City Hall loop.
Each toilet room has a free closet or closets, and a pay closet which
is furnished with a basin, mirror, soap dish, and towel rack. The
fixtures are porcelain, finished in dull nickel. The soil, vent and
water pipes are run in wall spaces, so as to be accessible. The rooms
are ventilated through the hollow columns of the kiosks, and each is
provided with an electric fan. They are heated by electric heaters.
The woodwork of the rooms is oak; the walls are red slate wainscot and
Keene cement.
Passengers may enter the body of the station without paying fare. The
train platforms are separated from the body of the station by
railings. At the more important stations, separate sets of entrances
are provided for incoming and outgoing passengers, the stairs at the
back of the station being used for entrances and those nearer the
track being used for exits.
[Illustration: CITY HALL STATION]
An example of the care used to obtain artistic effects can be seen at
the City Hall station. The road at this point is through an arched
tunnel. In order to secure consistency in treatment the roof of the
station is continued by a larger arch of special design. (See
photograph on this page.) At 168th Street, and at 181st Street,
and at Mott Avenue stations, where the road is far beneath the
surface, it has been possible to build massive arches over the
stations and tracks, with spans of 50 feet.
CHAPTER II
TYPES AND METHODS OF CONSTRUCTION
Five types of construction have been employed in building the road:
(1) the typical subway near the surface with flat roof and "I" beams
for the roof and sides, supported between tracks with steel bulb-angle
columns used on about 10.6 miles or 52.2 per cent. of the road; (2)
flat roof typical subway of reënforced concrete construction supported
between the tracks by steel bulb-angle columns, used for a short
distance on Lenox Avenue and on the Brooklyn portion of the Brooklyn
Extension, also on the Battery Park loop; (3) concrete lined tunnel
used on about 4.6 miles or 23 per cent. of the road, of which 4.2 per
cent. was concrete lined open cut work, and the remainder was rock
tunnel work; (4) elevated road on steel viaduct used on about 5 miles
or 24.6 per cent. of the road; (5) cast-iron tubes used under the
Harlem and East Rivers.
[Sidenote: _Typical
Subway_]
The general character of the flat roof "I" beam construction is shown
in photograph on page 28 and drawing on this page. The bottom
is of concrete. The side walls have "I" beam columns five feet apart,
between which are vertical concrete arches, the steel acting as a
support for the masonry and allowing the thickness of the walls to be
materially reduced from that necessary were nothing but concrete used.
The tops of the wall columns are connected by roof beams which are
supported by rows of steel columns between the tracks, built on
concrete and cut stone bases forming part of the floor system.
Concrete arches between the roof beams complete the top of the subway.
Such a structure is not impervious, and hence, there has been laid
behind the side walls, under the floor and over the roof a course of
two to eight thicknesses of felt, each washed with hot asphalt as
laid. In addition to this precaution against dampness, in three
sections of the subway (viz.: on Elm Street between Pearl and Grand
Streets, and on the approaches to the Harlem River tunnel, and on the
Battery Park Loop) the felt waterproofing has been made more effective
by one or two courses of hard-burned brick laid in hot asphalt, after
the manner sometimes employed in constructing the linings of
reservoirs of waterworks.
[Illustration: TYPICAL SECTION OF FOUR TRACK SUBWAY]
[Illustration: FOUR-TRACK SUBWAY--SHOWING CROSS-OVER SOUTH OF 18TH
STREET STATION]
In front of the waterproofing, immediately behind the steel columns,
are the systems of terra-cotta ducts in which the electric cables are
placed. The cables can be reached by means of manholes every 200 to
450 feet, which open into the subway and also into the street. The
number of these ducts ranges from 128 down to 32, and they are
connected with the main power station at 58th and 59th Streets and the
Hudson River by a 128-duct subway under the former street.
[Sidenote: _Reinforced
Concrete
Construction_]
The reinforced concrete construction substitutes for the steel roof
beams, steel rods, approximating 1-1/4 inches square, laid in varying
distances according to the different roof loads, from six to ten
inches apart. Rods 1-1/8 inches in diameter tie the side walls,
passing through angle columns in the walls and the bulb-angle columns
in the center. Layers of concrete are laid over the roof rods to a
thickness of from eighteen to thirty inches, and carried two inches
below the rods, imbedding them. For the sides similar square rods and
concrete are used and angle columns five feet apart. The concrete of
the side walls is from fifteen to eighteen inches thick. This type is
shown by photographs on page 41. The rods used are of both square
and twisted form.
[Illustration: LAYING SHEET WATERPROOFING IN BOTTOM]
[Illustration: SPECIAL BRICK AND ASPHALT WATERPROOFING]
[Sidenote: _Methods of
Construction
Typical
Subway_]
The construction of the typical subway has been carried on by a great
variety of methods, partly adopted on account of the conditions under
which the work had to be prosecuted and partly due to the personal
views of the different sub-contractors. The work was all done by open
excavation, the so-called "cut and cover" system, but the conditions
varied widely along different parts of the line, and different means
were adopted to overcome local difficulties. The distance of the rock
surface below the street level had a marked influence on the manner in
which the excavation of the open trenches could be made. In some
places this rock rose nearly to the pavement, as between 14th and 18th
Streets. At other places the subway is located in water-bearing loam
and sand, as in the stretch between Pearl and Grand Streets, where it
was necessary to employ a special design for the bottom, which is
illustrated by drawing on page 42.
This part of the route includes the former site of the ancient Collect
Pond, familiar in the early history of New York, and the excavation
was through made ground, the pond having been filled in for building
purposes after it was abandoned for supplying water to the city. The
excavations through Canal Street, adjacent, were also through made
ground, that street having been at one time, as its name implies, a
canal.
From the City Hall to 9th Street was sand, presenting no particular
difficulties except through the territory just described.
At Union Square rock was encountered on the west side of Fourth Avenue
from the surface down. On the east side of the street, however, at the
surface was sand, which extended 15 feet down to a sloping rock
surface. The tendency of the sand to a slide off into the rock
excavation required great care. The work was done, however, without
interference with the street traffic, which is particularly heavy at
that point.
[Illustration: DUCTS IN SIDE WALLS--EIGHT ONLY OF THE SIXTEEN LAYERS
ARE SHOWN]
[Illustration: REINFORCED CONCRETE CONSTRUCTION]
[Illustration: ROOF SHOWING CONCRETE-STEEL CONSTRUCTION--LENOX AVENUE
AND 140TH-141ST STREETS]
[Illustration: SECTION OF SUBWAY AT PEARL STREET
This construction was made necessary by encountering a layer of Peat
resting on Clay]
[Illustration: SURFACE RAILWAY TRACKS SUPPORTED OVER EXCAVATION ON
UPPER BROADWAY]
[Illustration: SUBDIVISION OF 36" AND 30" GAS MAINS OVER ROOF OF
SUBWAY--66TH STREET AND BROADWAY]
The natural difficulties of the route were increased by the network of
sewers, water and gas mains, steam pipes, pneumatic tubes, electric
conduits and their accessories, which filled the streets; and by the
surface railways and their conduits. In some places the columns of the
elevated railway had to be shored up temporarily, and in other places
the subway passes close to the foundations of lofty buildings, where
the construction needed to insure the safety of both subway and
buildings was quite intricate. As the subway is close to the surface
along a considerable part of its route, its construction involved the
reconstruction of all the underground pipes and ducts in many places,
as well as the removal of projecting vaults and buildings, and, in
some cases, the underpinning of their walls. A description in detail
of the methods of construction followed all along the line would make
an interesting book of itself. Space will only permit, however, an
account of how some of the more serious difficulties were overcome.
On Fourth Avenue, north of Union Square to 33d Street, there were two
electric conduit railway tracks in the center of the roadway and a
horse car track near each curb part of the distance. The two electric
car tracks were used for traffic which could not be interrupted,
although the horse car tracks could be removed without inconvenience.
These conditions rendered it impracticable to disturb the center of
the roadway, while permitting excavation near the curb. Well-timbered
shafts about 8 x 10 feet, in plan, were sunk along one curb line and
tunnels driven from them toward the other side of the street, stopping
about 3-1/2 feet beyond its center line. A bed of concrete was laid on
the bottom of each tunnel, and, when it had set, a heavy vertical
trestle was built on it. In this way trestles were built half across
the street, strong enough to carry all the street cars and traffic on
that half of the roadway. Cableways to handle the dirt were erected
near the curb line, spanning a number of these trestles, and then the
earth between them was excavated from the curb to within a few feet of
the nearest electric car track. The horse car tracks were removed.
Between the electric tracks a trench was dug until its bottom was
level with the tops of the trestles, about three feet below the
surface as a rule. A pair of heavy steel beams was then laid in this
trench on the trestles. Between these beams and the curb line a second
pair of beams were placed. In this way the equivalent of a bridge was
put up, the trestles acting as piers and the beams as girders. The
central portion of the roadway was then undermined and supported by
timbering suspended from the steel beams. The various gas and water
pipes were hung from timbers at the surface of the ground. About four
sections, or 150 feet, of the subway were built at a time in this
manner. When the work was completed along one side of the street it
was repeated in the same manner on the other side. This method of
construction was subsequently modified so as to permit work on both
sides of the street simultaneously. The manner in which the central
part of the roadway was supported remained the same and all of the
traffic was diverted to this strip.
[Illustration: SUPPORT OF ELEVATED RAILWAY STATION AT 42D STREET AND
SIXTH AVENUE]
Between 14th and 17th Streets, because of the proximity of the rock to
the surface, it was necessary to move the tracks of the electric
surface railway from the center of the street some twenty feet to the
east curb, without interrupting traffic, which was very heavy at all
times, the line being one of the main arteries of the Metropolitan
system. Four 12 x 12-inch timbers were laid upon the surface. Standard
cast-iron yokes were placed upon the timbers at the usual distance
apart. Upon this structure the regular track and slot rails were
placed. The space between the rails was floored over. Wooden boxes
were temporarily laid for the electric cables. The usual hand holes
and other accessories were built and the road operated on this timber
roadbed. The removal of the tracks was made necessary because the rock
beneath them and the concrete around the yokes was so closely united
as to be practically monolithic, precluding the use of explosives.
Attempts to remove the rock from under the track demonstrated that it
could not be done without destroying the yokes of the surface railway.
[Illustration: SUPPORTING ELEVATED RAILROAD BY EXTENSION GIRDER--64TH
STREET AND BROADWAY]
The method of undermining the tracks on Broadway from 60th to 104th
Streets was entirely different, for the conditions were not the same.
The street is a wide one with a 22-foot parkway in the center, an
electric conduit railway on either side, and outside each track a wide
roadway. The subway excavation extended about 10 feet outside each
track, leaving between it and the curb ample room for vehicles. The
construction problem, therefore, was to care for the car tracks with a
minimum interference with the excavation. This was accomplished by
temporary bridges for each track, each bridge consisting of a pair of
timber trusses about 55 feet long, braced together overhead high
enough to let a car pass below the bracing. These trusses were set up
on crib-work supports at each end, and the track hung from the lower
chords. (See photograph on page 42.) The excavation then proceeded
until the trench was finished and posts could be put into place
between its bottom and the track. When the track was securely
supported in this way, the trusses were lifted on flat cars and moved
ahead 50 feet.
At 66th Street station the subway roof was about 2 feet from the
electric railway yokes and structures of the street surface line. In
order to build at this point it was necessary to remove two large gas
mains, one 30 inches and the other 36 inches in diameter, and
substitute for them, in troughs built between the roof beams of the
subway, five smaller gas mains, each 24 inches in diameter. This was
done without interrupting the use of the mains.
[Illustration: MOVING BRICK AND CONCRETE RETAINING WALL TO MAKE ROOM
FOR THIRD TRACK--BROADWAY AND 134TH STREET]
At the station on 42d Street, between Park and Madison Avenues, where
there are five subway tracks, and along 42d Street to Broadway, a
special method of construction was employed which was not followed
elsewhere. The excavation here was about 35 feet deep and extended 10
to 15 feet into rock. A trench 30 feet wide was first sunk on the
south side of the street and the subway built in it for a width of two
tracks. Then, at intervals of 50 feet, tunnels were driven toward the
north side of the street. Their tops were about 4 feet above the roof
of the subway and their bottoms were on the roof. When they had been
driven just beyond the line of the fourth track, their ends were
connected by a tunnel parallel with the axis of the subway. The rock
in the bottom of all these tunnels was then excavated to its final
depth. In the small tunnel parallel with the subway axis, a bed of
concrete was placed and the third row of steel columns was erected
ready to carry the steel and concrete roof. When this work was
completed, the earth between the traverse tunnels was excavated, the
material above being supported on poling boards and struts. The roof
of the subway was then extended sidewise over the rock below from the
second to the third row of columns, and it was not until the roof was
finished that the rock beneath was excavated. In this way the subway
was finished for a width of four tracks. For the fifth track the earth
was removed by tunneling to the limits of the subway, and then the
rock below was blasted out.
[Illustration: MOVING WEST SIDE WALL TO WIDEN SUBWAY FOR THIRD
TRACK--135TH STREET AND BROADWAY]
[Illustration: SUBWAY THROUGH NEW "TIMES" BUILDING, SHOWING
INDEPENDENT CONSTRUCTION--THE WORKMEN STAND ON FLOOR GIRDERS OF
SUBWAY]
[Illustration: COLUMNS OF HOTEL BELMONT, PASSING THROUGH SUBWAY AT 42D
STREET AND PARK AVENUE]
In a number of places it was necessary to underpin the columns of the
elevated railways, and a variety of methods were adopted for the work.
A typical example of the difficulties involved was afforded at the
Manhattan Railway Elevated Station at Sixth Avenue and 42d Street. The
stairways of this station were directly over the open excavation for
the subway in the latter thoroughfare and were used by a large number
of people. The work was done in the same manner at each of the four
corners. Two narrow pits about 40 feet apart, were first sunk and
their bottoms covered with concrete at the elevation of the floor of
the subway. A trestle was built in each pit, and on these were placed
a pair of 3-foot plate girders, one on each side of the elevated
column, which was midway between the trestles. The column was then
riveted to the girders and was thus held independent of its original
foundations. Other pits were then sunk under the stairway and trestles
built in them to support it. When this work was completed it was
possible to carry out the remaining excavation without interfering
with the elevated railway traffic.
At 64th Street and Broadway, also, the whole elevated railway had to
be supported during construction. A temporary wooden bent was used to
carry the elevated structure. The elevated columns were removed until
the subway structure was completed at that point. (See photograph on
page 45.)
[Illustration: SMALL WATER MAINS BETWEEN STREET SURFACE AND SUBWAY
ROOF, SUBSTITUTED FOR ONE LARGE MAIN--125TH STREET AND LENOX AVE.]
[Illustration: SPECIAL CONSTRUCTION OF 6-1/2-FOOT SEWER, UNDER CHATHAM
SQUARE]
A feature of the construction which attracted considerable public
attention while it was in progress, was the underpinning of a part of
the Columbus Monument near the southwest entrance to Central Park.
This handsome memorial column has a stone shaft rising about 75 feet
above the street level and weighs about 700 tons. The rubble masonry
foundation is 45 feet square and rests on a 2-foot course of concrete.
The subway passes under its east side within 3 feet of its center,
thus cutting out about three-tenths of the original support. At this
place the footing was on dry sand of considerable depth, but on the
other side of the monument rock rose within 3 feet of the surface. The
steep slope of the rock surface toward the subway necessitated
particular care in underpinning the footings. The work was done by
first driving a tunnel 6 feet wide and 7 feet high under the monument
just outside the wall line of the subway. The tunnel was given a
2-foot bottom of concrete as a support for a row of wood posts a foot
square, which were put in every 5 feet to carry the footing above.
When these posts were securely wedged in place the tunnel was filled
with rubble masonry. This wall was strong enough to carry the weight
of the portion of the monument over the subway, but the monument had
to be supported to prevent its breaking off when undermined. To
support it thus a small tunnel was driven through the rubble masonry
foundation just below the street level and a pair of plate girders run
through it. A trestle bent was then built under each end of the
girders in the finished excavation for the subway. The girders were
wedged up against the top of the tunnel in the masonry and the
excavation was carried out under the monument without any injury to
that structure.
[Illustration: THREE PIPES SUBSTITUTED FOR LARGE BRICK SEWER AT 110TH
STREET AND LENOX AVENUE]
[Illustration: SEWER SIPHON AT 149TH STREET AND RAILROAD AVENUE]
[Illustration: CONCRETE SEWER BACK OF ELECTRIC DUCT MANHOLE--BROADWAY
AND 58TH STREET]
At 134th Street and Broadway a two-track structure of the steel beam
type about 200 feet long was completed. Approaching it from the south,
leading from Manhattan Valley Viaduct, was an open cut with retaining
walls 300 feet long and from 3 to 13 feet in height. After all this
work was finished (and it happened to be the first finished on the
subway), it was decided to widen the road to three tracks, and a
unique piece of work was successfully accomplished. The retaining
walls were moved bodily on slides, by means of jacks, to a line 6-1/4
feet on each side, widening the roadbed 12-1/2 feet, without a break
in either wall. The method of widening the steel-beam typical subway
portion was equally novel. The west wall was moved bodily by jacks
the necessary distance to bring it in line with the new position of
the west retaining wall. The remainder of the structure was then moved
bodily, also by jacks, 6-1/4 feet to the east. The new roof of the
usual type was then added over 12-1/2 feet of additional opening. (See
photographs on pages 46 and 47.)
[Illustration: CONCRETE SEWER BACK OF SIDE WALL, BROADWAY AND 56TH
STREET]
[Illustration: LARGE GAS AND WATER PIPES, RELAID BEHIND EACH SIDE WALL
ON ELM STREET]
Provision had to be made, not only for buildings along the route that
towered far above the street surface, but also for some which
burrowed far below the subway. Photograph on page 47 shows an
interesting example at 42d Street and Broadway, where the pressroom of
the new building of the "New York Times" is beneath the subway, the
first floor is above it, and the first basement is alongside of it.
Incidentally it should be noted that the steel structure of the
building and the subway are independent, the columns of the building
passing through the subway station.
[Illustration: DIFFICULT PIPE WORK--BROADWAY AND 70TH STREET]
At 42d Street and Park Avenue the road passes under the Hotel Belmont,
which necessitated the use of extra heavy steel girders and
foundations for the support of the hotel and reinforced subway
station. (See photograph on page 48.)
Along the east side of Park Row the ascending line of the "loop" was
built through the pressroom of the "New York Times" (the older
downtown building), and as the excavation was considerably below the
bottom of the foundation of the building, great care was necessary to
avoid any settlement. Instead of wood sheathing, steel channels were
driven and thoroughly braced, and construction proceeded without
disturbance of the building, which is very tall.
At 125th Street and Lenox Avenue one of the most complicated network
of subsurface structures was encountered. Street surface electric
lines with their conduits intersect. On the south side of 125th Street
were a 48-inch water main and a 6-inch water main, a 12-inch and two
10-inch gas pipes and a bank of electric light and power ducts. On the
north side were a 20-inch water main, one 6-inch, one 10-inch, and one
12-inch gas pipe and two banks of electric ducts. The headroom between
the subway roof and the surface of the street was 4.75 feet. It was
necessary to relocate the yokes of the street railway tracks on Lenox
Avenue so as to bring them directly over the tunnel roof-beams.
Between the lower flanges of the roof-beams, for four bents, were laid
heavy steel plates well stiffened, and in these troughs were laid four
20-inch pipes, which carried the water of the 48-inch main. (See
photograph on page 49.) Special castings were necessary to make
the connections at each end. The smaller pipes and ducts were
rearranged and carried over the roof or laid in troughs composed of
3-inch I-beams laid on the lower flanges of the roof-beams. In
addition to all the transverse pipes, there were numerous pipes and
duct lines to be relaid and rebuilt parallel to the subway and around
the station. The change was accomplished without stopping or delaying
the street cars. The water mains were shut off for only a few hours.
[Illustration: SPECIAL RIVETED RECTANGULAR WATER PIPE, OVER ROOF OF
SUBWAY AT 126TH STREET AND LENOX AVENUE]
As has been said, the typical subway near the surface was used for
about one-half of the road. Since the sewers were at such a depth as
to interfere with the construction of the subway, it meant that the
sewers along that half had to be reconstructed. This indicates but
very partially the magnitude of the sewer work, however, because
nearly as many main sewers had to be reconstructed off the route of
the subway as on the route; 7.21 miles of main sewers along the route
were reconstructed and 5.13 miles of main sewers off the route. The
reason why so many main sewers on streets away from the subway had to
be rebuilt, was that, from 42d Street, south, there is a natural
ridge, and before the construction of the subway sewers drained to the
East River and to the North River from the ridge. The route of the
subway was so near to the dividing line that the only way to care for
the sewers was, in many instances, to build entirely new outfall
sewers.
[Illustration: THREE-TRACK CONCRETE ARCH--117TH STREET AND BROADWAY]
A notable example of sewer diversion was at Canal Street, where the
flow of the sewer was carried into the East River instead of into the
Hudson River, permitting the sewer to be bulkheaded on the west side
and continued in use. On the east side a new main sewer was
constructed to empty into the East River. The new east-side sewer was
built off the route of the subway for over a mile. An interesting
feature in the construction was the work at Chatham Square, where a
6-1/2-foot circular brick conduit was built. The conjunction at this
point of numerous electric surface car lines, elevated railroad
pillars, and enormous vehicular street traffic, made it imperative
that the surface of the street should not be disturbed, and the sewer
was built by tunneling. This tunneling was through very fine running
sand and the section to be excavated was small. To meet these
conditions a novel method of construction was used. Interlocked
poling boards were employed to support the roof and were driven by
lever jacks, somewhat as a shield is driven in the shield system of
tunneling. The forward ends of the poling boards were supported by a
cantilever beam. The sides and front of the excavation were supported
by lagging boards laid flat against and over strips of canvas, which
were rolled down as the excavation progressed. The sewer was completed
and lined in lengths of from 1 foot to 4-1/2 feet, and at the maximum
rate of work about 12 feet of sewer were finished per week.
[Illustration: CONSTRUCTION OF FORT GEORGE TUNNEL]
At 110th Street and Lenox Avenue a 6-1/2-foot circular brick sewer
intersected the line of the subway at a level which necessitated its
removal or subdivision. The latter expedient was adopted, and three
42-inch cast-iron pipes were passed under the subway. (See photograph
on page 50.) At 149th Street and Railroad Avenue a sewer had to be
lowered below tide level in order to cross under the subway. To do
this two permanent inverted siphons were built of 48-inch cast-iron
pipe. Two were built in order that one might be used, while the other
could be shut off for cleaning, and they have proved very
satisfactory. This was the only instance where siphons were used. In
this connection it is worthy of note that the general changes referred
to gave to the city much better sewers as substitutes for the old
ones.
A number of interesting methods of providing for subsurface structures
are shown in photographs pages 51 to 54. From the General
Post-office at Park Row to 28th Street, just below the surface, there
is a system of pneumatic mail tubes for postal delivery. Of course,
absolutely no change in alignment could be permitted while these tubes
were in use carrying mail. It was necessary, therefore, to support
them very carefully. The slightest deviation in alignment would have
stopped the service.
[Illustration: TWO COLUMN BENT VIADUCT]
[Illustration: TRAVELER FOR ERECTING FORMS, CENTRAL PARK TUNNEL--(IN
THIS TUNNEL DUCTS ARE BUILT IN THE SIDEWALLS)]
[Sidenote: _Concrete-lined
Tunnel_]
Between 33d Street and 42d Street under Park Avenue, between 116th
Street and 120th Street under Broadway, between 157th Street and Fort
George under Broadway and Eleventh Avenue (the second longest
double-track rock tunnel in the United States, the Hoosac tunnel being
the only one of greater length), and between 104th Street and Broadway
under Central Park to Lenox Avenue, the road is in rock tunnel lined
with concrete. From 116th Street to 120th Street the tunnel is 37-1/2
feet wide, one of the widest concrete arches in the world. On the
section from Broadway and 103d Street to Lenox Avenue and 110th Street
under Central Park, a two-track subway was driven through micaceous
rock by taking out top headings and then two full-width benches. The
work was done from two shafts and one portal. All drilling for the
headings was done by an eight-hour night shift, using percussion
drills. The blasting was done early in the morning and the day gang
removed the spoil, which was hauled to the shafts and the portal in
cars drawn by mules. A large part of the rock was crushed for
concrete. The concrete floor was the first part of the lining to be
put in place. Rails were laid on it for a traveler having moulds
attached to its sides, against which the walls were built. A similar
traveler followed with the centering for the arch roof, a length of
about 50 feet being completed at one operation.
[Illustration: FOUR COLUMN (TOWER) VIADUCT CONSTRUCTION]
[Illustration: MANHATTAN VALLEY VIADUCT, LOOKING NORTH]
[Illustration: ERECTION OF ARCH, MANHATTAN VALLEY VIADUCT]
On the Park Avenue section from 34th Street to 41st Street two
separate double-track tunnels were driven below a double-track
electric railway tunnel, one on each side. The work was done from four
shafts, one at each end of each tunnel. At first, top headings were
employed at the north ends of both tunnels and at the south end of the
west tunnel; at the south end of the east tunnel a bottom heading was
used. Later, a bottom heading was also used at the south end of the
west tunnel. The rock was very irregular and treacherous in character,
and the strata inclined so as to make the danger of slips a serious
one. The two headings of the west tunnel met in February and those of
the east tunnel in March, 1902, and the widening of the tunnels to the
full section was immediately begun. Despite the adoption of every
precaution suggested by experience in such work, some disturbance of
the surface above the east tunnel resulted, and several house fronts
were damaged. The portion of the tunnel affected was bulkheaded at
each end, packed with rubble and grouted with Portland cement mortar
injected under pressure through pipes sunk from the street surface
above. When the interior was firm, the tunnel was redriven, using much
the same methods that are employed for tunnels through earth when the
arch lining is built before the central core, or dumpling of earth, is
removed. The work had to be done very slowly to prevent any further
settlement of the ground, and the completion of the widening of the
other parts of the tunnels also proceeded very slowly, because as soon
as the slip occurred a large amount of timbering was introduced, which
interfered seriously with the operations. After the lining was
completed, Portland cement grout was again injected under pressure,
through holes left in the roof, until further movement of the fill
overhead was absolutely prevented.
[Illustration: COMPLETED ARCH AT MANHATTAN STREET]
As has been said, the tunnel between 157th Street and Fort George is
the second longest two-track tunnel in the United States. It was built
in a remarkably short time, considering the fact that the work was
prosecuted from two portal headings and from two shafts. One shaft was
at 168th Street and the other at 181st Street, the work proceeding
both north and south from each shaft. The method employed for the work
(Photograph on page 56) was similar to that used under Central
Park. The shafts at 168th Street and at 181st Street were located at
those points so that they might be used for the permanent elevator
equipment for the stations at these streets. These stations each have
an arch span of about 50 feet, lined with brick.
[Sidenote: _Steel Viaduct_]
The elevated viaduct construction extends from 125th Street to 133d
Street and from Dyckman Street to Bailey Avenue on the western branch,
and from Brook and Westchester Avenues to Bronx Park on the eastern, a
total distance of about 5 miles. The three-track viaducts are carried
on two column bents where the rail is not more than 29 feet above the
ground level, and on four-column towers for higher structures. In the
latter case, the posts of a tower are 29 feet apart transversely and
20 or 25 feet longitudinally, as a rule, and the towers are from 70 to
90 feet apart on centers. The tops of the towers have X-bracing and
the connecting spans have two panels of intermediate vertical sway
bracing between the three pairs of longitudinal girders. In the low
viaducts, where there are no towers, every fourth panel has zigzag
lateral bracing in the two panels between the pairs of longitudinal
girders.
[Illustration: PROFILE OF HARLEM RIVER TUNNEL AND APPROACHES]
[Illustration: SECTION OF HARLEM RIVER TUNNEL DURING CONSTRUCTION]
[Illustration: ASSEMBLING IRON WORK ON PONTOON--HARLEM RIVER TUNNEL]
The towers have columns consisting as a rule of a 16 x 7/16-inch web
plate and four 6 x 4 x 5/8-inch bulb angles. The horizontal struts in
their cross-bracing are made of four 4 x 3-inch angles, latticed to
form an I-shaped cross-section. The X-bracing consists of single 5 x
3-1/2-inch angles. The tops of the columns have horizontal cap angles
on which are riveted the lower flanges of the transverse girders; the
end angles of the girder and the top of the column are also connected
by a riveted splice plate. The six longitudinal girders are
web-riveted to the transverse girders. The outside longitudinal girder
on each side of the viaduct has the same depth across the tower as in
the connecting span, but the four intermediate lines are not so deep
across the towers. In the single trestle bents the columns are the
same as those just described, but the diagonal bracing is replaced by
plate knee-braces.
The Manhattan Valley Viaduct on the West Side line, has a total length
of 2,174 feet. Its most important feature is a two-hinged arch of
168-1/2 feet span, which carries platforms shaded by canopies, but no
station buildings. The station is on the ground between the surface
railway tracks. Access to the platforms is obtained by means of
escalators. It has three lattice-girder two-hinge ribs 24-1/2 feet
apart on centers, the center line of each rib being a parabola. Each
half rib supports six spandrel posts carrying the roadway, the posts
being seated directly over vertical web members of the rib. The chords
of the ribs are 6 feet apart and of an H-section, having four 6 x
6-inch angles and six 15-inch flange and web plates for the center rib
and lighter sections for the outside ribs. The arch was erected
without false work.
[Illustration: SHOWING CONCRETE OVER IRON WORK--HARLEM RIVER TUNNEL]
The viaduct spans of either approach to the arch are 46 to 72 feet
long. All transverse girders are 31 feet 4 inches long, and have a 70
x 3/8-inch web plate and four 6 x 4-inch angles. The two outside
longitudinal girders of deck spans are 72 inches deep and the other 36
inches. All are 3/8-inch thick and their four flange angles vary in
size from 5 x 3-1/2 to 6 x 6 inches, and on the longest spans there
are flange plates. At each end of the viaduct there is a through span
with 90-inch web longitudinal girders.
Each track was proportioned for a dead load of 330 pounds per lineal
foot and a live load of 25,000 pounds per axle. The axle spacing in
the truck was 5 feet and the pairs of axles were alternately 27 and 9
feet apart. The traction load was taken at 20 per cent. of the live
load, and a wind pressure of 500 pounds per lineal foot was assumed
over the whole structure.
[Sidenote: _Tubes under
Harlem River_]
One of the most interesting sections of the work is that which
approaches and passes under the Harlem River, carrying the two tracks
of the East Side line. The War Department required a minimum depth of
20 feet in the river at low tide, which fixed the elevation of the
roof of the submerged part of the tunnel. This part of the line, 641
feet long, consists of twin single-track cast-iron cylinders 16 feet
in diameter enveloped in a large mass of concrete and lined with the
same material. The approach on either side is a double-track concrete
arched structure. The total length of the section is 1,500 feet.
The methods of construction employed were novel in subaqueous
tunneling and are partly shown on photographs on pages 62 and 63.
The bed of the Harlem River at the point of tunneling consists of mud,
silt, and sand, much of which was so nearly in a fluid condition that
it was removed by means of a jet. The maximum depth of excavation was
about 50 feet. Instead of employing the usual method of a shield and
compressed air at high pressure, a much speedier device was contrived.
The river crossing has been built in two sections. The west section
was first built, the War Department having forbidden the closing of
more than half the river at one time. A trench was dredged over the
line of the tunnel about 50 feet wide and 39 feet below low water.
This depth was about 10 feet above the sub-grade of the tunnel. Three
rows of piles were next driven on each side of the trench from the
west bank to the middle of the river and on them working platforms
were built, forming two wharves 38 feet apart in the clear. Piles were
then driven over the area to be covered by the subway, 6 feet 4 inches
apart laterally and 8 feet longitudinally. They were cut off about 11
feet above the center line of each tube and capped with timbers 12
inches square. A thoroughly-trussed framework was then floated over
the piles and sunk on them. The trusses were spaced so as to come
between each transverse row of piles and were connected by eight
longitudinal sticks or stringers, two at the top and two at the bottom
on each side. The four at each side were just far enough apart to
allow a special tongue and grooved 12-inch sheet piling to be driven
between them. This sheathing was driven to a depth of 10 to 15 feet
below the bottom of the finished tunnel.
A well-calked roof of three courses of 12-inch timbers, separated by
2-inch plank, was then floated over the piles and sunk. It had three
timber shafts 7 x 17 feet in plan, and when it was in place and
covered with earth it formed the top of a caisson with the sheet
piling on the sides and ends, the latter being driven after the roof
was in place. The excavation below this caisson was made under air
pressure, part of the material being blown out by water jets and the
remainder removed through the airlocks in the shafts. When the
excavation was completed, the piles were temporarily braced and the
concrete and cast-iron lining put in place, the piles being cut off as
the concrete bed was laid up to them.
The second or eastern section of this crossing was carried on by a
modification of the plan just mentioned. Instead of using a temporary
timber roof on the side walls, the permanent iron and concrete upper
half of the tunnels was employed as a roof for the caisson. The trench
was dredged nearly to sub-grade and its sides provided with wharves as
before, running out to the completed half of the work. The permanent
foundation piles were then driven and a timber frame sunk over them to
serve as a guide for the 12-inch sheet piling around the site. Steel
pilot piles with water jets were driven in advance of the wood-sheet
piles, and if they struck any boulders the latter were drilled and
blasted. The steel piles were withdrawn by a six-part tackle and
hoisting engine, and then the wooden piles driven in their place.
When the piling was finished, a pontoon 35 feet wide, 106 feet long,
and 12 feet deep was built between the wharves, and upon a separate
platform or deck on it the upper half of the cast-iron shells were
assembled, their ends closed by steel-plate diaphragms and the whole
covered with concrete. The pontoon was then submerged several feet,
parted at its center, and each half drawn out endwise from beneath the
floating top of the tunnel. The latter was then loaded and carefully
sunk into place, the connection with the shore section being made by
a diver, who entered the roof through a special opening. When it was
finally in place, men entered through the shore section and cut away
the wood bottom, thus completing the caisson so that work could
proceed below it as before. Three of these caissons were required to
complete the east end of the crossing.
[Illustration: LOOKING UP BROADWAY FROM TRINITY CHURCH--SHOWING
WORKING PLATFORM AND GAS MAINS TEMPORARILY SUPPORTED OVERHEAD]
The construction of the approaches to the tunnel was carried out
between heavy sheet piling. The excavation was over 40 feet deep in
places and very wet, and the success of the work was largely due to
the care taken in driving the 12-inch sheet piling.
[Sidenote: _Methods of
Construction
Brooklyn
Extension_]
A number of interesting features should be noted in the methods of
construction adopted on the Brooklyn Extension.
The types of construction on the Brooklyn Extension have already been
spoken of. They are (1) typical flat-roof steel beam subway from the
Post-office, Manhattan, to Bowling Green; (2) reinforced concrete
typical subway in Battery Park, Manhattan, and from Clinton Street to
the terminus, in Brooklyn; (3) two single track cast-iron-lined
tubular tunnels from Battery Park, under the East River, and under
Joralemon Street to Clinton Street, Brooklyn.
Under Broadway, Manhattan, the work is through sand, the vehicular
and electric street car traffic, the network of subsurface structures,
and the high buildings making this one of the most difficult portions
of the road to build. The street traffic is so great that it was
decided that during the daytime the surface of the street should be
maintained in a condition suitable for ordinary traffic. This was
accomplished by making openings in the sidewalk near the curb, at two
points, and erecting temporary working platforms over the street 16
feet from the surface. The excavations are made by the ordinary drift
and tunnel method. The excavated material is hoisted from the openings
to the platforms and passed through chutes to wagons. On the street
surface, over and in advance of the excavations, temporary plank decks
are placed and maintained during the drifting and tunneling
operations, and after the permanent subway structure has been erected
up to the time when the street surface is permanently restored. The
roof of the subway is about 5 feet from the surface of the street,
which has made it necessary to care for the gas and water mains. This
has been done by carrying the mains on temporary trestle structures
over the sidewalks. The mains will be restored to their former
position when the subway structure is complete.
From Bowling Green, south along Broadway, State Street and in Battery
Park, where the subway is of reinforced concrete construction, the
"open cut and cover" method is employed, the elevated and surface
railroad structures being temporarily supported by wooden and steel
trusses and finally supported by permanent foundations resting on the
subway roof. From Battery Place, south along the loop work, the
greater portion of the excavation is made below mean high-water level,
and necessitates the use of heavy tongue and grooved sheeting and the
operation of two centrifugal pumps, day and night.
The tubes under the East River, including the approaches, are each
6,544 feet in length. The tunnel consists of two cast-iron tubes
15-1/2 feet diameter inside, the lining being constructed of cast-iron
plates, circular in shape, bolted together and reinforced by grouting
outside of the plates and beton filling on the inside to the depth of
the flanges. The tubes are being constructed under air pressure
through solid rock from the Manhattan side to the middle of the East
River by the ordinary rock tunnel drift method, and on the Brooklyn
side through sand and silt by the use of hydraulic shields. Four
shields have been installed, weighing 51 tons each. They are driven by
hydraulic pressure of about 2,000 tons. The two shields drifting to
the center of the river from Garden Place are in water-bearing sand
and are operated under air pressure. The river tubes are on a 3.1 per
cent. grade and in the center of the river will reach the deepest
point, about 94 feet below mean high-water level.
The typical subway of reinforced concrete from Clinton Street to the
Flatbush Avenue terminus is being constructed by the method commonly
used on the Manhattan-Bronx route. From Borough Hall to the terminus
the route of the subway is directly below an elevated railway
structure, which is temporarily supported by timber bracing, having
its bearing on the street surface and the tunnel timbers. The
permanent support will be masonry piers built upon the roof of the
subway structure. Along this portion of the route are street surface
electric roads, but they are operated by overhead trolley and the
tracks are laid on ordinary ties. It has, therefore, been much less
difficult to care for them during the construction of the subway. Work
is being prosecuted on the Brooklyn Extension day and night, and in
Brooklyn the excavation is made much more rapidly by employing the
street surface trolley roads to remove the excavated material. Spur
tracks have been built and flat cars are used, much of the removal
being done at night.
CHAPTER III
POWER HOUSE BUILDING
The power house is situated adjacent to the North River on the block
bounded by West 58th Street, West 59th Street, Eleventh Avenue, and
Twelfth Avenue. The plans were adopted after a thorough study by the
engineers of Interborough Rapid Transit Company of all the large power
houses already completed and of the designs of the large power houses
in process of construction in America and abroad. The building is
large, and when fully equipped it will be capable of producing more
power than any electrical plant ever built, and the study of the
designs of other power houses throughout the world was pursued with
the principal object of reducing to a minimum the possibility of
interruption of service in a plant producing the great power required.
The type of power house adopted provides for a single row of large
engines and electric generators, contained within an operating room
placed beside a boiler house, with a capacity of producing,
approximately, not less than 100,000 horse power when the machinery is
being operated at normal rating.
[Sidenote: _Location
and General
Plan of
Power House_]
The work of preparing the detailed plans of the power house structure
was, in the main, completed early in 1902, and resulted in the present
plan, which may briefly be described as follows: The structure is
divided into two main parts--an operating room and a boiler house,
with a partition wall between the two sections. The face of the
structure on Eleventh Avenue is 200 feet wide, of which width the
boiler house takes 83 feet and the operating section 117 feet. The
operating room occupies the northerly side of the structure and the
boiler house the southerly side. The designers were enabled to employ
a contour of roof and wall section for the northerly side that was
identical with the roof and wall contour of the southerly side, so
that the building, when viewed from either end, presents a symmetrical
appearance with both sides of the building alike in form and design.
The operating room section is practically symmetrical in its
structure, with respect to its center; it consists of a central area,
with a truss roof over same along with galleries at both sides. The
galleries along the northerly side are primarily for the electrical
apparatus, while those along the southerly side are given up chiefly
to the steam-pipe equipment. The boiler room section is also
practically symmetrical with respect to its center.
A sectional scheme of the power house arrangement was determined on,
by which the structure was to consist of five generating sections,
each similar to the others in all its mechanical details; but, at a
later date, a sixth section was added, with space on the lot for a
seventh section. Each section embraces one chimney along with the
following generating equipment:--twelve boilers, two engines, each
direct connected to a 5,000 kilowatt alternator; two condensing
equipments, two boiler-feed pumps, two smoke-flue systems, and detail
apparatus necessary to make each section complete in itself. The only
variation is the turbine plant hereafter referred to. In addition to
the space occupied by the sections, an area was set aside, at the
Eleventh Avenue end of the structure, for the passage of the railway
spur from the New York Central tracks. The total length of the
original five-section power house was 585 feet 9-1/2 inches, but the
additional section afterwards added makes the over all length of the
structure 693 feet 9-3/4 inches. In the fourth section it was decided
to omit a regular engine with its 5,000 kilowatt generator, and in its
place substitute a 5,000 kilowatt lighting and exciter outfit.
Arrangements were made, however, so that this outfit can afterward be
replaced by a regular 5,000 kilowatt traction generator.
[Illustration: CROSS SECTION OF POWER HOUSE IN PERSPECTIVE]
The plan of the power station included a method of supporting the
chimneys on steel columns, instead of erecting them through the
building, which modification allowed for the disposal of boilers in
spaces which would otherwise be occupied by the chimney bases. By this
arrangement it was possible to place all the boilers on one floor
level. The economizers were placed above the boilers, instead of
behind them, which made a material saving in the width of the boiler
room. This saving permitted the setting aside of the aforementioned
gallery at the side of the operating room, closed off from both boiler
and engine rooms, for the reception of the main-pipe systems and for a
pumping equipment below it.
The advantages of the plan can be enumerated briefly as follows: The
main engines, combined with their alternators, lie in a single row
along the center line of the operating room with the steam or
operating end of each engine facing the boiler house and the opposite
end toward the electrical switching and controlling apparatus arranged
along the outside wall. Within the area between the boiler house and
operating room there is placed, for each engine, its respective
complement of pumping apparatus, all controlled by and under the
operating jurisdiction of the engineer for that engine. Each engineer
has thus full control of the pumping machinery required for his unit.
Symmetrically arranged with respect to the center line of each engine
are the six boilers in the boiler room, and the piping from these six
boilers forms a short connection between the nozzles on the boilers
and the throttles on the engine. The arrangement of piping is alike
for each engine, which results in a piping system of maximum
simplicity that can be controlled, in the event of difficulty, with a
degree of certainty not possible with a more complicated system. The
main parts of the steam-pipe system can be controlled from outside
this area.
The single tier of boilers makes it possible to secure a high and well
ventilated boiler room with ventilation into a story constructed above
it, aside from that afforded by the windows themselves. The boiler
room will therefore be cool in warm weather and light, and all
difficulties from escaping steam will be minimized. In this respect
the boiler room will be superior to corresponding rooms in plants of
older construction, where they are low, dark, and often very hot
during the summer season. The placing of the economizers, with their
auxiliary smoke flue connections, in the economizer room, all
symmetrically arranged with respect to each chimney, removes from the
boiler room an element of disturbance and makes it possible to pass
directly from the boiler house to the operating room at convenient
points along the length of the power house structure. The location of
each chimney in the center of the boiler house between sets of six
boilers divides the coal bunker construction into separate pockets by
which trouble from spontaneous combustion can be localized, and, as
described later, the divided coal bunkers can provide for the storage
of different grades of coal. The unit basis on which the economizer
and flue system is constructed will allow making repairs to any one
section without shutting off the portions not connected directly to
the section needing repair.
The floor of the power house between the column bases is a continuous
mass of concrete nowhere less than two feet thick. The massive
concrete foundations for the reciprocating engines contain each 1,400
yards of concrete above mean high water level, and in some cases have
twice as much below that point. The total amount of concrete in the
foundations of the finished power house is about 80,000 yards.
[Illustration: CROSS-SECTION OF POWER HOUSE]
Water for condensing purposes is drawn from the river and discharged
into it through two monolithic concrete tunnels parallel to the axis
of the building. The intake conduit has an oval interior, 10 x 8-1/2
feet in size, and a rectangular exterior cross-section; the outflow
tunnel has a horseshoe-shape cross-section and is built on top of the
intake tunnel. These tunnels were built throughout in open trench,
which, at the shore end, was excavated in solid rock. At the river end
the excavation was, at some places, almost entirely through the fill
and mud and was made in a cofferdam composed chiefly of sheet piles.
As it was impossible to drive these piles across the old timber crib
which formed the old dock front, the latter was cut through by a
pneumatic caisson of wooden-stave construction, which formed part of
one side of the cofferdam. At the river end of the cofferdam the rock
was so deep that the concrete could not be carried down to its
surface, and the tunnel section was built on a foundation of piles
driven to the rock and cut off by a steam saw 19-1/2 feet below mean
hightide. This section of the tunnel was built in a 65 x 48-foot
floating caisson 24 feet deep. The concrete was rammed in it around
the moulds and the sides were braced as it sunk. After the tunnel
sections were completed, the caisson was sunk, by water ballast, to a
bearing on the pile foundation.
Adjacent to the condensing water conduits is the 10 x 15-foot
rectangular concrete tunnel, through which the underground coal
conveyor is installed between the shore end of the pier and the power
house.
[Sidenote: _Steel Work_]
The steel structure of the power house is independent of the walls,
the latter being self-supporting and used as bearing walls only for a
few of the beams in the first floor. Although structurally a single
building, in arrangement it is essentially two, lying side by side and
separated by a brick division wall.
There are 58 transverse and 9 longitudinal rows of main columns, the
longitudinal spacing being 18 feet and 36 feet for different rows,
with special bracing in the boiler house to accommodate the
arrangement of boilers. The columns are mainly of box section, made up
of rolled or built channels and cover plates. They are supported by
cast-iron bases, resting on the granite capstones of the concrete
foundation piers.
Both the boiler house and the engine house have five tiers of floor
framing below the flat portion of the roof, the three upper tiers of
the engine house forming galleries on each side of the operating room,
which is clear for the full height of the building.
The boiler house floors are, in general, framed with transverse plate
girders and longitudinal rolled beams, arranged to suit the particular
requirements of the imposed loads of the boilers, economizers, coal,
etc., while the engine-room floors and pipe and switchboard galleries
are in general framed with longitudinal plate girders and transverse
beams.
There are seven coal bunkers in the boiler house, of which five are 77
feet and two 41 feet in length by 60 feet in width at the top, the
combined maximum capacity being 18,000 tons. The bunkers are separated
from each other by the six chimneys spaced along the center line of
the boiler house. The bottom of the bunkers are at the fifth floor, at
an elevation of about 66 feet above the basement. The bunkers are
constructed with double, transverse, plate girder frames at each line
of columns, combined with struts and ties, which balance the outward
thrust of the coal against the sides. The frames form the outline of
the bunkers with slides sloping at 45 degrees, and carry longitudinal
I-beams, between which are built concrete arches, reinforced with
expanded metal, the whole surface being filled with concrete over the
tops of the beams and given a two-inch granolithic finish.
[Illustration: 58TH ST. POWER HOUSE--GENERAL PLAN OF COAL BUNKERS AND
ECONOMIZERS.]
[Illustration: 58TH ST. POWER HOUSE--GENERAL PLAN OF MAIN OPERATING
FLOOR.]
The six chimneys, spaced 108 feet apart, and occupying the space
between the ends of the adjacent coal bunkers, are supported on
plate-girder platforms in the fifth floor, leaving the space below
clear for a symmetrical arrangement of the boilers and economizers
from end to end of the building. The platforms are framed of
single-web girders 8 feet deep, thoroughly braced and carrying on
their top flanges a grillage of 20-inch I-beam. A system of bracing
for both the chimney platforms and coal bunkers is carried down to the
foundations in traverse planes about 30 feet apart.
The sixth tier of beams constitute a flat roof over a portion of the
building at the center and sides. In the engine room, at this level,
which is 64 feet above the engine-room floor, are provided the two
longitudinal lines of crane runway girders upon which are operated the
engine-room cranes. Runways for 10-ton hand cranes are also provided
for the full length of the boiler room, and for nearly the full length
of the north panel in the engine room.
Some of the loads carried by the steel structure are as follows: In
the engine house, operating on the longitudinal runways as mentioned,
are one 60-ton and one 25-ton electric traveling crane of 75 feet
span. The imposed loads of the steam-pipe galleries on the south side
and the switchboard galleries on the north side are somewhat
irregularly distributed, but are equivalent to uniform loads of 250 to
400 pounds per square foot. In the boiler house the weight of coal
carried is about 45 tons per longitudinal foot of the building; the
weight of the brick chimneys is 1,200 tons each; economizers, with
brick setting, about 4-1/2 tons per longitudinal foot; suspended
weight of the boilers 96 tons each, and the weight of the boiler
setting, carried on the first floor framing, 160 tons each. The weight
of structural steel used in the completed building is about 11,000
tons.
[Sidenote: _Power House
Superstructure_]
The design of the facework of the power house received the personal
attention of the directors of the company, and its character and the
class of materials to be employed were carefully considered. The
influence of the design on the future value of the property and the
condition of the environment in general were studied, together with
the factors relating to the future ownership of the plant by the city.
Several plans were taken up looking to the construction of a power
house of massive and simple design, but it was finally decided to
adopt an ornate style of treatment by which the structure would be
rendered architecturally attractive and in harmony with the recent
tendencies of municipal and city improvements from an architectural
standpoint. At the initial stage of the power house design Mr.
Stanford White, of the firm of McKim, Mead & White, of New York,
volunteered his services to the company as an adviser on the matter of
the design of the facework, and, as his offer was accepted, his
connection with the work has resulted in the development of the
present exterior design and the selection of the materials used.
The Eleventh Avenue façade is the most elaborately treated, but the
scheme of the main façade is carried along both the 58th and 59th
Street fronts. The westerly end of the structure, facing the river,
may ultimately be removed in case the power house is extended to the
Twelfth Avenue building line for the reception of fourteen generating
equipments; and for this reason this wall is designed plainly of less
costly material.
The general style of the facework is what may be called French
Renaissance, and the color scheme has, therefore, been made rather
light in character. The base of the exterior walls has been finished
with cut granite up to the water table, above which they have been
laid up with a light colored buff pressed brick. This brick has been
enriched by the use of similarly colored terra-cotta, which appears in
the pilasters, about the windows, in the several entablatures, and in
the cornice and parapet work. The Eleventh Avenue façade is further
enriched by marble medallions, framed with terra-cotta, and by a title
panel directly over the front of the structure.
The main entrance to the structure is situated at its northeast
corner, and, as the railroad track passes along just inside the
building, the entrance proper is the doorway immediately beyond the
track, and opens into the entrance lobby. The doorway is trimmed with
cut granite and the lobby is finished with a marble wainscoting.
The interior of the operating room is faced with a light,
cream-colored pressed brick with an enameled brick wainscoting, eight
feet high, extending around the entire operating area; the wainscoting
is white except for a brown border and base. The offices, the toilets
and locker rooms are finished and fitted with materials in harmony
with the high-class character of the building. The masonry-floor
construction consists of concrete reinforced with expanded metal, and
except where iron or other floor plates are used, or where tile or
special flooring is laid, the floor is covered with a hard cement
granolithic finish.
In the design of the interior arrangements, the value of a generous
supply of stairways was appreciated, in order that all parts of the
structure might be made readily accessible, especially in the boiler
house section. In the boiler house and machinery portion of the plant
the stairways, railings, and accessories are plainly but strongly
constructed. The main stairways are, however, of somewhat ornate
design, with marble and other trim work, and the railings of the main
gallery construction are likewise of ornate treatment. All exterior
doors and trim are of metal and all interior carpenter work is done
with Kalomein iron protection, so that the building, in its strictest
sense, will contain no combustible material.
[Sidenote: _Chimneys_]
The complete 12-unit power house will have six chimneys, spaced 108
feet apart on the longitudinal center line of the boiler room, each
chimney being 15 feet in inside diameter at the top, which is 225 feet
above the grate bars. Each will serve the twelve boilers included in
the section of which it is the center, these boilers having an
aggregate of 72,000 square feet of heating surface. By these
dimensions each chimney has a fair surplus capacity, and it is
calculated that, with economizers in the path of the furnace gases,
there will be sufficient draft to meet a demand slightly above the
normal rating of the boilers. To provide for overload capacity, as may
be demanded by future conditions, a forced draft system will be
supplied, as described later.
As previously stated, the chimneys are all supported upon the steel
structure of the building at an elevation of 76 feet above the
basement floor and 63 feet above the grates. The supporting platforms
are, in each case, carried on six of the building columns (the three
front columns of two groups of boilers on opposite sides of the center
aisle of the boiler room), and each platform is composed of single-web
plate girders, well braced and surmounted by a grillage of 20-inch
I-beams. The grillage is filled solidly with concrete and flushed
smooth on top to receive the brickwork of the chimney.
Each chimney is 162 feet in total height of brickwork above the top of
the supporting platform, and each chimney is 23 feet square in the
outside dimension at the base, changing to an octagonal form at a
point 14 feet 3 inches above the base. This octagonal form is carried
to a height of 32 feet 6 inches above the base, at which point the
circular section of radial brick begins.
The octagonal base of the chimney is of hard-burned red brick three
feet in thickness between the side of the octagon and the interior
circular section. The brick work is started from the top of the
grillage platform with a steel channel curb, three feet in depth,
through which two lines of steel rods are run in each direction, thus
binding together the first three feet of brickwork, and designed to
prevent any flaking at the outside. At a level of three feet above the
bottom of the brickwork, a layer of water-proofing is placed over the
interior area and covered with two courses of brick, upon which are
built diagonal brick walls, 4 inches thick, 12 inches apart, and about
18 inches in height. These walls are themselves perforated at
intervals, and the whole is covered with hand-burned terra-cotta
blocks, thus forming a cellular air space, which communicates with the
exterior air and serves as an insulation against heat for the
steelwork beneath. A single layer of firebrick completes the flooring
of the interior area, which is also flush with the bottom of the flue
openings.
There are two flue openings, diametrically opposite, and 6 feet wide
by 17 feet high to the crown of the arched top. They are lined with
fire brick, which joins the fire-brick lining of the interior of the
shaft, this latter being bonded to the red-brick walls to a point 6
feet below the top of the octagon, and extended above for a height of
14 feet within the circular shaft, as an inner shell. The usual baffle
wall is provided of fire brick, 13 inches thick, extending diagonally
across the chimney, and 4 feet above the tops of the flue openings.
Where the chimney passes through the roof of the boiler house, a steel
plate and angle curb, which clears the chimney by 6 inches at all
points, is provided in connection with the roof framing. This is
covered by a hood flashed into the brickwork, so that the roof has no
connection with or bearing upon the chimney.
At a point 4 feet 6 inches below the cap of the chimney the brickwork
is corbeled out for several courses, forming a ledge, around the
outside of which is placed a wrought-iron railing, thus forming a
walkway around the circumference of the chimney top. The cap is of
cast iron, surmounted by eight 3 x 1-inch wrought-iron ribs, bent over
the outlet and with pointed ends gathered together at the center. The
lightning conductors are carried down the outside of the shaft to the
roof and thence to the ground outside of the building. Galvanized iron
ladder rungs were built in the brickwork, for ladders both inside and
outside the shaft.
The chimneys, except for the octagonal red-brick base, are constructed
of the radial perforated bricks. The lightning rods are tipped with
pointed platinum points about 18 inches long.
[Sidenote: _North River
Pier_]
Exceptional facilities have been provided for the unloading of coal
from vessels, or barges, which can be brought to the northerly side of
the recently constructed pier at the foot of West 58th Street. The
pier was specially built by the Department of Docks and Ferries and is
700 feet long and 60 feet wide.
The pier construction includes a special river wall across 58th Street
at the bulkhead line through which the condensing water will be taken
from and returned to the river. Immediately outside the river wall and
beneath the deck of the pier, there is a system of screens through
which the intake water is passed. On each side where the water enters
the screen chamber, is a heavy steel grillage; inside this is a system
of fine screens arranged so that the several screens can be raised, by
a special machine, for the purpose of cleaning. The advantages of a
well-designed screening outfit has been appreciated, and considerable
care has been exercised to make it as reliable and effective as
possible.
At each side of the center of the pier, just below the deck, there are
two discharge water conduits constructed of heavy timber, to conduct
the warm water from the condensers away from the cold water intakes at
the screens. Two water conduits are employed, in order that one may be
repaired or renewed while using the other; in fact, the entire pier is
constructed with the view of renewal without interference in the
operation for which it was provided.
CHAPTER IV
POWER PLANT FROM COAL PILE TO SHAFTS OF ENGINES AND TURBINES
From the minute and specific description in Chapter III, a clear idea
will have been obtained of the power house building and its adjuncts,
as well as of the features which not only go to make it an
architectural landmark, but which adapt it specifically for the vital
function that it is called upon to perform. We now come to a review
and detailed description of the power plant equipment in its general
relation to the building, and "follow the power through" from the coal
pile to the shafts of the engines or steam turbines attached to the
dynamos which generate current for power and for light.
[Sidenote: _Coal and Ash
Handling
Equipment_]
The elements of the coal handling equipment comprise a movable
electric hoisting tower with crushing and weighing apparatus--a system
of horizontal belt conveyors, with 30-inch belts, to carry the crushed
and weighed coal along the dock and thence by tunnel underground to
the southwest corner of the power house; a system of 30-inch belt
conveyors to elevate the coal a distance of 110 feet to the top of the
boiler house, at the rate of 250 tons per hour or more, if so desired,
and a system of 20-inch belt conveyors to distribute it horizontally
over the coal bunkers. These conveyors have automatic self reversing
trippers, which distribute the coal evenly in the bunkers. For
handling different grades of coal, distributing conveyors are arranged
underneath the bunkers for delivering the coal from a particular
bunker through gates to the downtake hoppers in front of the boilers,
as hereafter described.
The equipment for removing ashes from the boiler room basement and for
storing and delivering the ashes to barges, comprises the following
elements: A system of tracks, 24 inches gauge, extending under the
ash-hopper gates in the boiler-house cellar and extending to an
elevated storage bunker at the water front. The rolling stock consists
of 24 steel cars of 2 tons capacity, having gable bottoms and side
dumping doors. Each car has two four-wheel pivoted trucks with
springs. Motive power is supplied by an electric storage battery
locomotive. The cars deliver the ashes to an elevating belt conveyor,
which fills the ash bunker. This will contain 1,000 tons, and is built
of steel with a suspension bottom lined with concrete. For delivering
stored ashes to barges, a collecting belt extends longitudinally under
the pocket, being fed by eight gates. It delivers ashes to a loading
belt conveyor, the outboard end of which is hinged so as to vary the
height of delivery and to fold up inside the wharf line when not in
use.
The coal handling system in question was adopted because any serious
interruption of service would be of short duration, as any belt, or
part of the belt mechanism, could quickly be repaired or replaced. The
system also possessed advantages with respect to the automatic even
distribution of coal in the bunkers, by means of the self reversing
trippers. These derive their power from the conveying belts. Each
conveyor has a rotary cleaning brush to cleanse the belt before it
reaches the driving pulley and they are all driven by induction
motors.
The tower frame and boom are steel. The tower rolls on two rails along
the dock and is self-propelling. The lift is unusually short; for the
reason that the weighing apparatus is removed horizontally to one side
in a separate house, instead of lying vertically below the crusher.
This arrangement reduces by 40 per cent. the lift of the bucket, which
is of the clam-shell type of forty-four cubic feet capacity. The
motive power for operating the bucket is perhaps the most massive and
powerful ever installed for such service. The main hoist is directly
connected to a 200 horse-power motor with a special system of control.
The trolley engine for hauling the bucket along the boom is also
direct coupled to a multipolar motor.
The receiving hopper has a large throat, and a steel grizzly in it
which sorts out coal small enough for the stokers and bypasses it
around the crusher. The crusher is of the two-roll type, with
relieving springs, and is operated by a motor, which is also used for
propelling the tower. The coal is weighed in duplex two-ton hoppers.
Special attention has been given to providing for the comfort and
safety of the operators. The cabs have baywindow fronts, to enable the
men to have an unobstructed view of the bucket at all times without
peering through slots in the floor. Walks and hand lines are provided
on both sides of the boom for safe inspection. The running ropes pass
through hardwood slides, which cover the slots in the engine house
roof to exclude rain and snow.
This type of motive power was selected in preference to trolley
locomotives for moving the ash cars, owing to the rapid destruction of
overhead lines and rail bonds by the action of ashes and water. The
locomotive consists of two units, each of which has four driving
wheels, and carries its own motor and battery. The use of two units
allows the locomotive to round curves with very small overhangs, as
compared with a single-body locomotive. Curves of 12 feet radius can
be turned with ease. The gross weight of the locomotive is about five
tons, all of which is available for traction.
[Sidenote: _Coal
Downtakes_]
The coal from the coal bunkers is allowed to flow down into the boiler
room through two rows of downtakes, one on each side of the central
gangway or firing place. Each bunker has eight cast-iron outlets, four
on each side, and to these outlets are bolted gate valves for shutting
off the coal from the corresponding downtakes. From these gates the
downtakes lead to hoppers which are on the economizer floor, and from
these hoppers the lower sets of downtakes extend down to the boilers.
Just above the hoppers on the economizer floor the coal downtakes are
provided with valves and chutes to feed the coal, either into the
hopper or into the distributing flight conveyor alongside of it. These
distributing conveyors, one corresponding with each row of downtakes,
permits the feeding of coal from any bunker or bunkers to all the
boilers when desired. They are the ordinary type of flight conveyor,
capable of running in either direction and provided with gates in the
bottom of the trough for feeding into the several above mentioned
hoppers. In order to eliminate the stresses that would develop in a
conveyor of the full length of the building, the conveyors are of half
the entire length, with electric driving engines in the center of each
continuous line. The installation of this conveyor system, in
connection with the coal downtakes, makes it possible to carry a
high-grade coal in some of the bunkers for use during periods of heavy
load and a cheaper grade in other bunkers for the periods of light
load.
To provide means for shutting off the coal supply to each boiler, a
small hopper is placed just over each boiler, and the downtake feeding
into it is provided with a gate at its lower end. Two vertical
downtakes extend down from the boiler hopper to the boiler room floor
or to the stokers, as the case may be, and they are hinged just below
the boiler hopper to allow their being drawn up out of the way when
necessary to inspect the boiler tubes.
[Illustration: WEST END POWER HOUSE IN COURSE OF ERECTION]
Wherever the direction of flow of the coal is changed, poke holes are
provided in the downtakes to enable the firemen to break any arching
tendency of the coal in the downtakes. All parts of the downtakes are
of cast iron, except the vertical parts in front of the boilers, which
are of wrought-iron pipe. These vertical downtakes are 10 inches in
inside diameter, while all others are 14 inches in inside diameter.
[Sidenote: _Main Boiler
Room_]
The main boiler room is designed to receive ultimately seventy-two
safety water tube three drum boilers, each having 6,008 square feet of
effective heating surface, by which the aggregate heating surface of
the boiler room will be 432,576 square feet.
There are fifty-two boilers erected in pairs, or batteries, and
between each battery is a passageway five feet wide. The boilers are
designed for a working steam pressure of 225 pounds per square inch
and for a hydraulic test pressure of 300 pounds per square inch. Each
boiler is provided with twenty-one vertical water tube sections, and
each section is fourteen tubes high. The tubes are of lap welded,
charcoal iron, 4 inches in diameter and 18 feet long. The drums are 42
inches in diameter and 23 feet and 10 inches long. All parts are of
open-hearth steel; the shell plates are 9/16 of an inch thick and the
drum head plates 11/16 inch, and in this respect the thickness of
material employed is slightly in excess of standard practice. Another
advance on standard practice is in the riveting of the circular seams,
these being lap-jointed and double riveted. All longitudinal seams are
butt-strapped, inside and outside, and secured by six rows of rivets.
Manholes are only provided for the front heads, and each front head is
provided with a special heavy bronze pad, for making connection to the
stop and check feed water valve.
[Illustration: OPERATING ROOM SHOWING CONDENSERS--POWER HOUSE]
The setting of the boiler embodies several special features which are
new in boiler erection. The boilers are set higher up from the floor
than in standard practice, the center of the drums being 19 feet above
the floor line. This feature provides a higher combustion chamber, for
either hand-fired grates or automatic stokers; and for inclined grate
stokers the fire is carried well up above the supporting girders under
the side walls, so that these girders will not be heated by proximity
to the fire.
As regards the masonry setting, practically the entire inside surface
exposed to the hot gases is lined with a high grade of fire brick. The
back of the setting, where the rear cleaning is done, is provided with
a sliding floor plate, which is used when the upper tubes are being
cleaned. There is also a door at the floor line and another at a
higher level for light and ventilation when cleaning. Over the tubes
arrangements have been made for the reception of superheating
apparatus without changing the brickwork. Where the brick walls are
constructed, at each side of the building columns at the front,
cast-iron plates are erected to a height of 8 feet on each side of the
column. An air space is provided between each cast-iron plate and the
column, which is accessible for cleaning from the boiler front; the
object of the plates and air space being to prevent the transmission
of heat to the steel columns.
An additional feature of the boiler setting consists in the employment
of a soot hopper, back of each bridge wall, by which the soot can be
discharged into ash cars in the basement. The main ash hoppers are
constructed of 1/2-inch steel plate, the design being a double
inverted pyramid with an ash gate at each inverted apex. The hoppers
are well provided with stiffening angles and tees, and the capacity of
each is about 80 cubic feet.
In front of all the boilers is a continuous platform of open-work
cast-iron plates, laid on steel beams, the level of the platform being
8 feet above the main floor. The platform connects across the firing
area, opposite the walk between the batteries, and at these points
this platform is carried between the boiler settings. At the rear of
the northerly row of boilers the platform runs along the partition
wall, between the boiler house and operating room and at intervals
doorways are provided which open into the pump area. The level of the
platform is even with that of the main operating room floor, so that
it may be freely used by the water tenders and by the operating
engineers without being obstructed by the firemen or their tools. The
platform in front of the boilers will also be used for cleaning
purposes, and, in this respect, it will do away with the unsightly and
objectionable scaffolds usually employed for this work. The water
tenders will also be brought nearer to the water columns than when
operating on the main floor. The feed-water valves will be regulated
from the platform, as well as the speed of the boiler-feed pumps.
Following European practice, each boiler is provided with two water
columns, one on each outside drum, and each boiler will have one steam
gauge above the platform for the water tenders and one below the
platform for the firemen. The stop and check valves on each boiler
drum have been made specially heavy for the requirements of this power
house, and this special increase of weight has been applied to all the
several minor boiler fittings.
Hand-fired grates of the shaking pattern have been furnished for
thirty-six boilers, and for each of these grates a special lower front
has been constructed. These fronts are of sheet steel, and the coal
passes down to the floor through two steel buckstays which have been
enlarged for the purpose. There are three firing doors and the sill of
each door is 36 inches above the floor. The gate area of the
hand-fired grates is 100 square feet, being 8 feet deep by 12 feet 6
inches wide.
The twelve boilers, which will receive coal from the coal bunker
located between the fourth and fifth chimneys, have been furnished
with automatic stokers.
It is proposed to employ superheaters to the entire boiler plant.
The boiler-room ceiling has been made especially high, and in this
respect the room differs from most power houses of similar
construction. The distance from the floor to the ceiling is 35 feet,
and from the floor plates over the boilers to the ceiling is 13 feet.
Over each boiler is an opening to the economizer floor above, covered
with an iron grating. The height of the room, as well as the feature
of these openings, and the stairway wells and with the large extent of
window opening in the south wall, will make the room light and
especially well ventilated. Under these conditions the intense heat
usually encountered over boilers will largely be obviated.
In addition to making provisions for the air to escape from the upper
part of the boiler room, arrangements have been provided for allowing
the air to enter at the bottom. This inflow of air will take place
through the southerly row of basement windows, which extend above the
boiler room floor, and through the wrought-iron open-work floor
construction extending along in the rear of the northerly row of
boilers.
A noteworthy feature of the boiler room is the 10-ton hand-power
crane, which travels along in the central aisle through the entire
length of the structure. This crane is used for erection and for heavy
repair, and its use has greatly assisted the speedy assembling of the
boiler plant.
[Sidenote: _Blowers and
Air Ducts_]
In order to burn the finer grades of anthracite coal in sufficient
quantities to obtain boiler rating with the hand-fired grates, and in
order to secure a large excess over boiler rating with other coals, a
system of blowers and air ducts has been provided in the basement
under the boilers. One blower is selected for every three boilers,
with arrangements for supplying all six boilers from one blower.
The blowers are 11 feet high above the floor and 5 feet 6 inches wide
at the floor line. Each blower is direct-connected to a two crank
7-1/2 x 13 x 6-1/2-inch upright, automatic, compound, steam engine of
the self-enclosed type, and is to provide a sufficient amount of air
to burn 10,000 pounds of combustible per hour with 2 inches of water
pressure in the ash pits.
[Sidenote: _Smoke Flues
and
Economizers_]
The smoke flue and economizer construction throughout the building is
of uniform design, or, in other words, the smoke flue and economizer
system for one chimney is identical with that for every other chimney.
In each case, the system is symmetrically arranged about its
respective chimney, as can be seen by reference to the plans.
The twelve boilers for each chimney are each provided with two round
smoke uptakes, which carry the products of combustion upward to the
main smoke flue system on the economizer floor. A main smoke flue is
provided for each group of three boilers, and each pair of main smoke
flues join together on the center line of the chimney, where in each
case one common flue carries the gases into the side of the chimney.
The two common flues last mentioned enter at opposite sides of the
chimney. The main flues are arranged and fitted with dampers, so that
the gases can pass directly to the chimney, or else they can be
diverted through the economizers and thence reach the chimney.
The uptakes from each boiler are constructed of 3/8-inch plate and
each is lined with radial hollow brick 4 inches thick. Each is
provided with a damper which operates on a shaft turning in roller
bearings. The uptakes rest on iron beams at the bottom, and at the
top, where they join the main flue, means are provided to take up
expansion and contraction.
The main flue, which rests on the economizer floor, is what might be
called a steel box, constructed of 3/8-inch plate, 6 feet 4 inches
wide and 13 feet high. The bottom is lined with brick laid flat and
the sides with brick walls 8 inches thick, and the top is formed of
brick arches sprung between.
[Sidenote: _Steam Piping_]
The sectional plan adopted for the power house has made a uniform and
simple arrangement of steam piping possible, with the piping for each
section, except that of the turbine bay, identical with that for every
other section. Starting with the six boilers for one main engine, the
steam piping may be described as follows: A cross-over pipe is erected
on each boiler, by means of which and a combination of valves and
fittings the steam may be passed through the superheater. In the
delivery from each boiler there is a quick-closing 9-inch valve, which
can be closed from the boiler room floor by hand or from a distant
point individually or in groups of six. Risers with 9-inch
wrought-iron goose necks connect each boiler to the steam main, where
9-inch angle valves are inserted in each boiler connection. These
valves can be closed from the platform over the boilers, and are
grouped three over one set of three boilers and three over the
opposite set.
The main from the six boilers is carried directly across the boiler
house in a straight line to a point in the pipe area where it rises to
connect to the two 14-inch steam downtakes to the engine throttles. At
this point the steam can also be led downward to a manifold to which
the compensating tie lines are connected. These compensating lines are
run lengthwise through the power house for the purpose of joining the
systems together, as desired. The two downtakes to the engine
throttles drop to the basement, where each, through a goose neck,
delivers into a receiver and separating tank and from the tank through
a second goose neck into the corresponding throttle.
A quick-closing valve appears at the point where the 17-inch pipe
divides into the two 14-inch downtakes and a similar valve is provided
at the point where the main connects to the manifold. The first valve
will close the steam to the engine and the second will control the
flow of steam to and from the manifold. These valves can be operated
by hand from a platform located on the wall inside the engine room, or
they can be closed from a distant point by hydraulic apparatus. In the
event of accident the piping to any engine can be quickly cut out or
that system of piping can quickly be disconnected from the
compensating system.
The pipe area containing, as mentioned, the various valves described,
together with the manifolds and compensating pipes, is divided by
means of cross-walls into sections corresponding to each pair of main
engines. Each section is thus separated from those adjoining, so that
any escape of steam in one section can be localized and, by means of
the quick-closing valves, the piping for the corresponding pair of
main engines can be disconnected from the rest of the power house.
[Illustration: VIEW FROM TOP OF CHIMNEY SHOWING WATER FRONTAGE--POWER
HOUSE]
All cast iron used in the fittings is called air-furnace iron, which
is a semi-steel and tougher than ordinary iron. All line and bent pipe
is of wrought iron, and the flanges are loose and made of wrought
steel. The shell of the pipe is bent over the face of the flange. All
the joints in the main steam line, above 2-1/2 inches in size, are
ground joints, metal to metal, no gaskets being used.
Unlike the flanges ordinarily used in this country, special extra
strong proportions have been adopted, and it may be said that all
flanges and bolts used are 50 per cent. heavier than the so-called
extra heavy proportions used in this country.
[Sidenote: _Water Piping_]
The feed water will enter the building at three points, the largest
water service being 12 inches in diameter, which enters the structure
at its southeast corner. The water first passes through fish traps
and thence through meters, and from them to the main reservoir tanks,
arranged along the center of the boiler house basement. The water is
allowed to flow into each tank by means of an automatic float valve.
The water will be partly heated in these reservoir tanks by means of
hot water discharged from high-pressure steam traps. In this way the
heat contained in the drainage from the high-pressure steam is, for
the most part, returned to the boilers. From the reservoir tanks the
water is conducted to the feed-water pumps, by which it is discharged
through feed-water heaters where it is further heated by the exhaust
steam from the condensing and feed-water pumps. From the feed-water
heaters the water will be carried direct to the boilers; or through
the economizer system to be further heated by the waste gases from the
boilers.
[Illustration: PORTION OF MAIN STEAM PIPING IN PIPE AREA]
Like the steam-pipe system, the feed-water piping is laid out on the
sectional plan, the piping for the several sections being identical,
except for the connections from the street service to the reservoir
tanks. The feed-water piping is constructed wholly of cast iron,
except the piping above the floor line to the boilers, which is of
extra heavy semi-annealed brass with extra heavy cast-iron fittings.
[Sidenote: _Engine and
Turbine
Equipment_]
The engine and turbine equipment under contract embraces nine 8,000 to
11,000 horse power main engines, direct-connected to 5,000 kilowatt
generators, three steam turbines, direct-connected to 1,875 kilowatt
lighting generators and two 400 horse power engines, direct-connected
to 250 kilowatt exciter generators.
[Sidenote: _Main Engines_]
The main engines are similar in type to those installed in the 74th
Street power house of the Manhattan Division of the Interborough Rapid
Transit Company, i. e., each consists of two component compound
engines, both connected to a common shaft, with the generator placed
between the two component engines. The type of engine is now well
known and will not be described in detail, but as a comparison of
various dimensions and features of the Manhattan and Rapid Transit
engines may be of interest, the accompanying tabulation is submitted:
Manhattan. Rapid Transit.
Diameter of high-pressure cylinders, inches, 44 42
Diameter of low-pressure cylinders, inches, 88 86
Stroke, inches, 60 60
Speed, revolutions per minute, 75 75
Steam pressure at throttle, pounds, 150 175
Indicated horse power at best efficiency, 7,500 7,500
Diameter of low-pressure piston rods, inches, 8 10
Diameter of high-pressure piston rods, inches, 8 10
Diameter of crank pin, inches, 18 20
Length of crank pin, inches, 18 18
Double Ported Single Ported
Type of Low-Pressure Valves. Corliss Corliss
Type of High-Pressure Valves. Corliss Poppet Type
Diameter of shaft in journals, inches, 34 34
Length of journals, inches, 60 60
Diameter of shaft in hub of revolving
element, inches 37-1/16 37-1/16
The guarantees under which the main engines are being furnished, and
which will govern their acceptance by the purchaser, are in substance
as follows: First. The engine will be capable of operating
continuously when indicating 11,000 horse power with 175 lbs. of steam
pressure, a speed of 75 revolutions and a 26-inch vacuum without
normal wear, jar, noise, or other objectionable results. Second. It
will be suitably proportioned to withstand in a serviceable manner all
sudden fluctuations of load as are usual and incidental to the
generation of electrical energy for railway purposes. Third. It will
be capable of operating with an atmospheric exhaust with two pounds
back pressure at the low pressure cylinders, and when so operating,
will fulfill all the operating requirements, except as to economy and
capacity. Fourth. It will be proportioned so that when occasion shall
require it can be operated with a steam pressure at the throttles of
200 pounds above atmospheric pressure under the before mentioned
conditions of the speed and vacuum. Fifth. It will be proportioned so
that it can be operated with steam pressure at the throttle of 200
pounds above atmospheric pressure under the before mentioned condition
as to speed when exhausting in the atmosphere. Sixth. The engine will
operate successfully with a steam pressure at the throttle of 175
pounds above atmosphere, should the temperature of the steam be
maintained at the throttle at from 450 to 500 degrees Fahr. Seventh.
It will not require more than 12-1/4 pounds of dry steam per indicated
horse power per hour, when indicating 7,500 horse power at 75
revolutions per minute, when the vacuum of 26 inches at the low
pressure cylinders, with a steam pressure at the throttle of 175
pounds and with saturated steam at the normal temperature due to its
pressure. The guarantee includes all of the steam used by the engine
or by the jackets or reheater.
The new features contained within the engine construction are
principally: First, the novel construction of the high-pressure
cylinders, by which only a small strain is transmitted through the
valve chamber between the cylinder and the slide-surface casting.
This is accomplished by employing heavy bolts, which bolt the shell of
the cylinder casting to the slide-surface casting, said bolts being
carried past and outside the valve chamber. Second, the use of poppet
valves, which are operated in a very simple manner from a wrist plate
on the side of the cylinder, the connections from the valves to the
wrist plate and the connections from the wrist plate to the eccentric
being similar to the parts usually employed for the operation of
Corliss valves.
Unlike the Manhattan engines, the main steam pipes are carried to the
high-pressure cylinders under the floor and not above it. Another
modification consists in the use of an adjustable strap for the
crank-pin boxes instead of the marine style of construction at the
crank-pin end of the connecting rod.
The weight of the revolving field is about 335,000 pounds, which gives
a flywheel effect of about 350,000 pounds at a radius of gyration of
11 feet, and with this flywheel inertia the engine is designed so that
any point on the revolving element shall not, in operation, lag behind
nor forge ahead of the position that it would have if the speed were
absolutely uniform, by an amount greater than one-eighth of a natural
degree.
[Sidenote: _Turbo-Generators_]
Arrangements have been made for the erection of four turbo generators,
but only three have been ordered. They are of the multiple expansion
parallel flow type, consisting of two turbines arranged tandem
compound. When operating at full load each of the two turbines,
comprising one unit, will develop approximately equal power for direct
connection to an alternator giving 7,200 alternations per minute at
11,000 volts and at a speed of 1,200 revolutions per minute. Each unit
will have a normal output of 1,700 electrical horse power with a steam
pressure of 175 pounds at the throttle and a vacuum in the exhaust
pipe of 27 inches, measured by a mercury column and referred to a
barometric pressure of 30 inches. The turbine is guaranteed to operate
satisfactorily with steam superheated to 450 degrees Fahrenheit. The
economy guaranteed under the foregoing conditions as to initial and
terminal pressure and speed is as follows: Full load of 1,250
kilowatts, 15.7 pounds of steam per electrical horse-power hour;
three-quarter load, 937-1/2 kilowatts, 16.6 pounds per electrical
horse-power hour; one-half load, 625 kilowatts, 18.3 pounds; and
one-quarter load, 312-1/2 kilowatts, 23.2 pounds. When operating under
the conditions of speed and steam pressure mentioned, but with a
pressure in the exhaust pipe of 27 inches vacuum by mercury column
(referred to 30 inches barometer), and with steam at the throttle
superheated 75 degrees Fahrenheit above the temperature of saturated
steam at that pressure, the guaranteed steam consumption is as
follows: Full load, 1,250 kilowatts, 13.8 pounds per electrical
horse-power hour; three-quarter load, 937-1/2 kilowatts, 14.6 pounds;
one-half load, 625 kilowatts, 16.2 pounds; and one-quarter load,
312-1/2 kilowatts, 20.8 pounds.
[Sidenote: _Exciter
Engines_]
The two exciter engines are each direct connected to a 250 kilowatt
direct current generator. Each engine is a vertical quarter-crank
compound engine with a 17-inch high pressure cylinder and a 27-inch
low-pressure cylinder with a common 24-inch stroke. The engines will
be non-condensing, for the reason that extreme reliability is desired
at the expense of some economy. They will operate at best efficiency
when indicating 400 horse power at a speed of 150 revolutions per
minute with a steam pressure of 175 pounds at the throttle. Each
engine will have a maximum of 600 indicated horse power.
[Sidenote: _Condensing
Equipment_]
Each engine unit is supplied with its own condenser equipment,
consisting of two barometric condensing chambers, each attached as
closely as possible to its respective low-pressure cylinder. For each
engine also is provided a vertical circulating pump along with a
vacuum pump and, for the sake of flexibility, the pumps are cross
connected with those of other engines and can be used interchangeably.
The circulating pumps are vertical, cross compound pumping engines
with outside packed plungers. Their foundations are upon the basement
floor level and the steam cylinders extend above the engine-room
floor; the starting valves and control of speed is therefore entirely
under the supervision of the engineer. Each pump has a normal capacity
of 10,000,000 gallons of water per day, so that the total pumping
capacity of all the pumps is 120,000,000 gallons per day. While the
head against which these pumps will be required to work, when assisted
by the vacuum in the condenser, is much less than the total lift from
low tide water to the entrance into the condensing chambers, they are
so designed as to be ready to deliver the full quantity the full
height, if for any reason the assistance of the vacuum should be lost
or not available at times of starting up. A temporary overload can but
reduce the vacuum only for a short time and the fluctuations of the
tide, or even a complete loss of vacuum cannot interfere with the
constant supply of water, the governor simply admitting to the
cylinders the proper amount of steam to do the work. The high-pressure
steam cylinder is 10 inches in diameter and the low-pressure is 20
inches; the two double-acting water plungers are each 20 inches in
diameter, and the stroke is 30 inches for all. The water ends are
composition fitted for salt water and have valve decks and plungers
entirely of that material.
[Illustration: COAL UNLOADING TOWER ON WEST 58TH STREET PIER]
The dry vacuum pumps are of the vertical form, and each is located
alongside of the corresponding circulating pump. The steam cylinders
also project above the engine-room floor. The vacuum cylinder is
immediately below the steam cylinder and has a valve that is
mechanically operated by an eccentric on the shaft. These pumps are of
the close-clearance type, and, while controlled by a governor, can be
changed in speed while running to any determined rate.
[Sidenote: _Exhaust
Piping_]
From each atmospheric exhaust valve, which is direct-connected to the
condensing chamber at each low-pressure cylinder, is run downward a
30-inch riveted-steel exhaust pipe. At a point just under the
engine-room floor the exhaust pipe is carried horizontally around the
engine foundations, the two from each pair of engines uniting in a
40-inch riser to the roof. This riser is between the pair of engines
and back of the high-pressure cylinder, thus passing through the
so-called pipe area, where it also receives exhaust steam from the
pump auxiliaries. At the roof the 40-inch riser is run into a 48-inch
stand pipe. This is capped with an exhaust head, the top of which is
35 feet above the roof.
All the exhaust piping 30 inches in diameter and over is
longitudinally riveted steel with cast-iron flanges riveted on to it.
Expansion joints are provided where necessary to relieve the piping
from the strains due to expansion and contraction, and where the
joints are located near the engine and generator they are of
corrugated copper. The expansion joints in the 40-inch risers above
the pipe area are ordinarily packed slip joints.
The exhaust piping from the auxiliaries is carried directly up into
the pipe area, where it is connected with a feed-water heater, with
means for by-passing the latter. Beyond the heater it joins the
40-inch riser to the roof. The feed-water heaters are three-pass,
vertical, water-tube heaters, designed for a working water pressure of
225 pounds per square inch.
The design of the atmospheric relief valve received special
consideration. A lever is provided to assist the valve to close, while
a dash pot prevents a too quick action in either direction.
[Sidenote: _Compressed
Air_]
The power house will be provided with a system for supplying
compressed air to various points about the structure for cleaning
electrical machinery and for such other purposes as may arise. It will
also be used for operating whistles employed for signaling. The air is
supplied to reservoir tanks by two vertical, two-stage,
electric-driven air compressors.
[Sidenote: _Oil System_]
For the lubrication of the engines an extensive oil distributing and
filtering system is provided. Filtered oil will be supplied under
pressure from elevated storage tanks, with a piping system leading to
all the various journals. The piping to the engines is constructed on
a duplicate, or crib, system, by which the supply of oil cannot be
interrupted by a break in any one pipe. The oil on leaving the engines
is conducted to the filtering tanks. A pumping equipment then
redelivers the oil to the elevated storage tanks.
All piping carrying filtered oil is of brass and fittings are inserted
at proper pipes to facilitate cleaning. The immediate installation
includes two oil filtering tanks at the easterly end of the power
house, but the completed plant contemplates the addition of two extra
filtering tanks at the westerly end of the structure.
[Sidenote: _Cranes, Shops,
Etc._]
The power house is provided with the following traveling cranes: For
the operating room: One 60-ton electric traveling crane and one 25-ton
electric traveling crane. For the area over the oil switches: one
10-ton hand-operated crane. For the center aisle of the boiler room:
one 10-ton hand-operated crane. The span of both of the electric
cranes is 74 feet 4 inches and both cranes operate over the entire
length of the structure.
The 60-ton crane has two trolleys, each with a lifting capacity, for
regular load, of 50 tons. Each trolley is also provided with an
auxiliary hoist of 10 tons capacity. When loaded, the crane can
operate at the following speeds: Bridge, 200 feet per minute;
trolley, 100 feet per minute; main hoist, 10 feet per minute; and
auxiliary hoist, 30 feet per minute. The 25-ton crane is provided with
one trolley, having a lifting capacity, for regular load, of 25 tons,
together with auxiliary hoist of 5 tons. When loaded, the crane can
operate at the following speeds: bridge, 250 feet per minute; trolley,
100 feet per minute; main hoist, 12 feet per minute; and auxiliary
hoist, 28 feet per minute.
The power house is provided with an extensive tool equipment for a
repair and machine shop, which is located on the main gallery at the
northerly side of the operating room.
[Illustration: 5,000 K. W. ALTERNATOR--MAIN POWER HOUSE]
CHAPTER V
SYSTEM OF ELECTRICAL SUPPLY
[Sidenote: _Energy from
Engine Shaft
to Third Rail_]
The system of electrical supply chosen for the subway comprises
alternating current generation and distribution, and direct current
operation of car motors. Four years ago, when the engineering plans
were under consideration, the single-phase alternating current railway
motor was not even in an embryonic state, and notwithstanding the
marked progress recently made in its development, it can scarcely yet
be considered to have reached a stage that would warrant any
modifications in the plans adopted, even were such modifications
easily possible at the present time. The comparatively limited
headroom available in the subway prohibited the use of an overhead
system of conductors, and this limitation, in conjunction with the
obvious desirability of providing a system permitting interchangeable
operation with the lines of the Manhattan Railway system practically
excluded tri-phase traction systems and led directly to the adoption
of the third-rail direct current system.
[Illustration: SIDE AND END ELEVATIONS OF ALTERNATOR.]
[Illustration: SIDE ELEVATION AND CROSS SECTION OF ALTERNATOR WITH
PART CUT AWAY TO SHOW CONSTRUCTION.]
It being considered impracticable to predict with entire certainty the
ultimate traffic conditions to be met, the generator plant has been
designed to take care of all probable traffic demands expected to
arise within a year or two of the beginning of operation of the
system, while the plans permit convenient and symmetrical increase to
meet the requirements of additional demand which may develop. Each
express train will comprise five motor cars and three trail cars, and
each local train will comprise three motor cars and two trail cars.
The weight of each motor car with maximum live load is 88,000 pounds,
and the weight of each trailer car 66,000 pounds.
The plans adopted provide electric equipment at the outstart capable
of operating express trains at an average speed approximating
twenty-five miles per hour, while the control system and motor units
have been so chosen that higher speeds up to a limit of about thirty
miles per hour can be attained by increasing the number of motor cars
providing experience in operation demonstrates that such higher speeds
can be obtained with safety.
The speed of local trains between City Hall and 96th Street will
average about 15 miles an hour, while north of 96th Street on both the
West side and East side branches their speed will average about 18
miles an hour, owing to the greater average distance between local
stations.
As the result of careful consideration of various plans, the company's
engineers recommended that all the power required for the operation of
the system be generated in a single power house in the form of
three-phase alternating current at 11,000 volts, this current to be
generated at a frequency of 25 cycles per second, and to be delivered
through three-conductor cables to transformers and converters in
sub-stations suitably located with reference to the track system, the
current there to be transformed and converted to direct current for
delivery to the third-rail conductor at a potential of 625 volts.
[Illustration: OPERATING GALLERY IN SUB-STATION]
[Illustration: GENERAL DIAGRAM OF 11,000 VOLT CIRCUITS IN MAIN POWER
STATION]
Calculations based upon contemplated schedules require for traction
purposes and for heating and lighting cars, a maximum delivery of
about 45,000 kilowatts at the third rail. Allowing for losses in the
distributing cables, in transformers and converters, this implies a
total generating capacity of approximately 50,000 kilowatts, and
having in view the possibility of future extensions of the system it
was decided to design and construct the power house building for the
ultimate reception of eleven 5,000-kilowatt units for traction current
in addition to the lighting sets. Each 5,000-kilowatt unit is capable
of delivering during rush hours an output of 7,500 kilowatts or
approximately 10,000 electrical horse power and, setting aside one
unit as a reserve, the contemplated ultimate maximum output of the
power plant, therefore, is 75,000 kilowatts, or approximately 100,000
electrical horse power.
[Sidenote: _Power
House_]
The power house is fully described elsewhere in this publication, but
it is not inappropriate to refer briefly in this place to certain
considerations governing the selection of the generating unit, and the
use of engines rather than steam turbines.
[Illustration: OIL SWITCHES--MAIN POWER STATION]
The 5,000-kilowatt generating unit was chosen because it is
practically as large a unit of the direct-connected type as can be
constructed by the engine builders unless more than two bearings be
used--an alternative deemed inadvisable by the engineers of the
company. The adoption of a smaller unit would be less economical of
floor space and would tend to produce extreme complication in so large
an installation, and, in view of the rapid changes in load which in
urban railway service of this character occur in the morning and again
late in the afternoon, would be extremely difficult to operate.
The experience of the Manhattan plant has shown, as was anticipated in
the installation of less output than this, the alternators must be put
in service at intervals of twenty minutes to meet the load upon the
station while it is rising to the maximum attained during rush hours.
After careful consideration of the possible use of steam turbines as
prime-movers to drive the alternators, the company's engineers decided
in favor of reciprocating engines. This decision was made three years
ago and, while the steam turbine since that time has made material
progress, those responsible for the decision are confirmed in their
opinion that it was wise.
[Illustration: PART OF BUS BAR COMPARTMENTS--MAIN POWER STATION]
[Sidenote: _Alternators_]
The alternators closely resemble those installed by the Manhattan
Railway Company (now the Manhattan division of the Interborough Rapid
Transit Company) in its plant on the East River, between 74th Street
and 75th Street. They differ, however, in having the stationary
armature divided into seven castings instead of six, and in respect to
details of the armature winding. They are three-phase machines,
delivering twenty-five cycle alternating currents at an effective
potential of 11,000 volts. They are 42 feet in height, the diameter
of the revolving part is 32 feet, its weight, 332,000 pounds, and the
aggregate weight of the machine, 889,000 pounds. The design of the
engine dynamo unit eliminates the auxiliary fly wheel generally used
in the construction of large direct-connected units prior to the
erection of the Manhattan plant, the weight and dimensions of the
revolving alternator field being such with reference to the turning
moment of the engine as to secure close uniformity of rotation, while
at the same time this construction results in narrowing the engine and
reducing the engine shafts between bearings.
[Illustration: REAR VIEW OF BUS BAR COMPARTMENTS--MAIN POWER STATION]
[Illustration: DUCT LINE ACROSS 58TH STREET 32 DUCTS]
Construction of the revolving parts of the alternators is such as to
secure very great strength and consequent ability to resist the
tendency to burst and fly apart in case of temporary abnormal speed
through accident of any kind. The hub of the revolving field is of
cast steel, and the rim is carried not by the usual spokes but by two
wedges of rolled steel. The construction of the revolving field is
illustrated on pages 91 and 92. The angular velocity of the
revolving field is remarkably uniform. This result is due primarily to
the fact that the turning movement of the four-cylinder engine is far
more uniform than is the case, for example, with an ordinary
two-cylinder engine. The large fly-wheel capacity of the rotating
element of the machine also contributes materially to secure
uniformity of rotation.
[Illustration: MAIN CONTROLLING BOARD IN POWER STATION]
[Illustration: CONTROL AND INSTRUMENT BOARD--MAIN POWER STATION]
The alternators have forty field poles and operates at seventy-five
revolutions per minute. The field magnets constitute the periphery of
the revolving field, the poles and rim of the field being built up by
steel plates which are dovetailed to the driving spider. The heavy
steel end plates are bolted together, the laminations breaking joints
in the middle of the pole. The field coils are secured by copper
wedges, which are subjected to shearing strains only. In the body of
the poles, at intervals of approximately three inches, ventilating
spaces are provided, these spaces registering with corresponding air
ducts in the external armature. The field winding consists of copper
strap on edge, one layer deep, with fibrous material cemented in place
between turns, the edges of the strap being exposed.
[Illustration: DUCTS UNDER PASSENGER STATION PLATFORM
64 DUCTS]
The armature is stationary and exterior to the field. It consists of a
laminated ring with slots on its inner surface and supported by a
massive external cast-iron frame. The armature, as has been noted,
comprises seven segments, the topmost segment being in the form of a
small keystone. This may be removed readily, affording access to any
field coil, which in this way may be easily removed and replaced. The
armature winding consists of U-shaped copper bars in partially closed
slots. There are four bars per slot and three slots per phase per
pole. The bars in any slot may be removed from the armature without
removing the frame. The alternators, of course, are separately
excited, the potential of the exciting current used being 250 volts.
As regards regulation, the manufacturer's guarantee is that at 100 per
cent. power factor if full rated load be thrown off the e. m. f. will
rise 6 per cent. with constant speed and constant excitation. The
guarantee as to efficiency is as follows: On non-inductive load, the
alternators will have an efficiency of not less than 90.5 per cent. at
one-quarter load; 94.75 per cent. at one-half load; 96.25 per cent. at
three-quarters load; 97 per cent. at full load, and 97.25 per cent. at
one and one-quarter load. These figures refer, of course, to
electrical efficiency, and do not include windage and bearing
friction. The machines are designed to operate under their rated full
load with rise of temperature not exceeding 35 degrees C. after
twenty-four hours.
[Illustration: THREE-CONDUCTOR NO. 000 CABLE FOR 11,000 VOLT
DISTRIBUTION]
[Sidenote: _Exciters_]
To supply exciting current for the fields of the alternators and to
operate motors driving auxiliary apparatus, five 250-kilowatt direct
current dynamos are provided. These deliver their current at a
potential of 250 volts. Two of them are driven by 400 horse-power
engines of the marine type, to which they are direct-connected, while
the remaining three units are direct-connected to 365 horse-power
tri-phase induction motors operating at 400 volts. A storage battery
capable of furnishing 3,000 amperes for one hour is used in
co-operation with the dynamos provided to excite the alternators. The
five direct-current dynamos are connected to the organization of
switching apparatus in such a way that each unit may be connected at
will either to the exciting circuits or to the circuits through which
auxiliary motors are supplied.
The alternators for which the new Interborough Power House are
designed will deliver to the bus bars 100,000 electrical horse power.
The current delivered by these alternators reverses its direction
fifty times per second and in connecting dynamos just coming into
service with those already in operation the allowable difference in
phase relation at the instant the circuit is completed is, of course,
but a fraction of the fiftieth of a second. Where the power to be
controlled is so great, the potential so high, and the speed
requirements in respect to synchronous operation so exacting, it is
obvious that the perfection of control attained in some of our modern
plants is not their least characteristic.
[Sidenote: _Switching
Apparatus_]
The switch used for the 11,000 volt circuits is so constructed that
the circuits are made and broken under oil, the switch being
electrically operated. Two complete and independent sets of bus bars
are used, and the connections are such that each alternator and each
feeder may be connected to either of these sets of bus bars at the
will of the operator. From alternators to bus bars the current passes,
first, through the alternator switch, and then alternatively through
one or the other of two selector switches which are connected,
respectively, to the two sets of bus bars.
[Illustration: INSIDE WALL OF TUNNEL SHOWING 64 DUCTS]
Provision is made for an ultimate total of twelve sub-stations, to
each of which as many as eight feeders may be installed if the
development of the company's business should require that number. But
eight sub-stations are required at present, and to some of these not
more than three feeders each are necessary. The aggregate number of
feeders installed for the initial operation of the subway system is
thirty-four.
Each feeder circuit is provided with a type H-oil switch arranged to
be open and closed at will by the operator, and also to open
automatically in the case of abnormal flow of current through the
feeder. The feeders are arranged in groups, each group being supplied
from a set of auxiliary bus bars, which in turn receives its supply
from one or the other of the two sets of main bus bars; means for
selection being provided as in the case of the alternator circuits by
a pair of selector switches, in this case designated as group
switches. The diagram on page 93 illustrates the essential
features of the organization and connections of the 11,000 volt
circuits in the power house.
[Illustration: MANHOLES IN SIDE WALL OF SUBWAY]
Any and every switch can be opened or closed at will by the operator
standing at the control board described. The alternator switches are
provided also with automatic overload and reversed current relays, and
the feeder switches, as above mentioned, are provided with automatic
overload relays. These overload relays have a time attachment which
can be set to open the switch at the expiration of a predetermined
time ranging from .3 of a second to 5 seconds.
[Illustration: CONVERTER FLOOR PLAN
SUB-STATION NO. 14]
The type H-oil switch is operated by an electric motor through the
intervention of a mechanism comprising powerful springs which open and
close the switch with great speed. This switch when opened introduces
in each of the three sides of the circuit two breaks which are in
series with each other. Each side of the circuit is separated from the
others by its location in an enclosed compartment, the walls of which
are brick and soapstone. The general construction of the switch is
illustrated by the photograph on page 94.
[Illustration: CROSS SECTION SUB-STATION NO. 14]
[Illustration: INTERIOR OF SUB-STATION NO. 11]
[Illustration: LONGITUDINAL SECTION SUB-STATION NO. 14]
Like all current-carrying parts of the switches, the bus bars are
enclosed in separate compartments. These are constructed of brick,
small doors for inspection and maintenance being provided opposite all
points where the bus bars are supported upon insulators. The
photographs on pages 95 and 96 are views of a part of the bus bar
and switch compartments.
[Illustration: TWO GROUPS OF TRANSFORMERS]
The oil switches and group bus bars are located upon the main floor
and extend along the 59th Street wall of the engine room a distance of
about 600 feet. The main bus bars are arranged in two lines of brick
compartments, which are placed below the engine-room floor. These bus
bars are arranged vertically and are placed directly beneath the rows
of oil switches located upon the main floor of the power house. Above
these rows of oil switches and the group bus bars, galleries are
constructed which extend the entire length of the power house, and
upon the first of these galleries at a point opposite the middle of
the power house are located the control board and instrument board, by
means of which the operator in charge regulates and directs the entire
output of the plant, maintaining a supply of power at all times
adequate to the demands of the transportation service.
[Illustration: MOTOR-GENERATORS AND BATTERY BOARD FOR CONTROL
CIRCUITS--SUB-STATION]
[Illustration: 1,500 K. W. ROTARY CONVERTER]
[Sidenote: _The Control
Board_]
The control board is shown in the photograph on page 97. Every
alternator switch, every selector switch, every group switch, and
every feeder switch upon the main floor is here represented by a small
switch. The small switch is connected into a control circuit which
receives its supply of energy at 110 volts from a small motor
generator set and storage battery. The motors which actuate the large
oil switches upon the main floor are driven by this 110 volt control
current, and thus in the hands of the operator the control switches
make or break the relatively feeble control currents, which, in turn,
close or open the switches in the main power circuits. The control
switches are systematically assembled upon the control bench board in
conjunction with dummy bus bars and other apparent (but not real)
metallic connections, the whole constituting at all times a correct
diagram of the existing connections of the main power circuits. Every
time the operator changes a connection by opening or closing one of
the main switches, he necessarily changes his diagram so that it
represents the new conditions established by opening or closing the
main switch. In connection with each control switch two small
bull's-eye lamps are used, one red, to indicate that the corresponding
main switch is closed, the other green, to indicate that it is open.
These lamps are lighted when the moving part of the main switch
reaches approximately the end of its travel. If for any reason,
therefore, the movement of the control switch should fail to actuate
the main switch, the indicator lamp will not be lighted.
[Illustration: MOTOR-GENERATOR SET SUPPLYING ALTERNATING CURRENT FOR
BLOCK SIGNALS AND MOTOR-GENERATOR STARTING SET]
The control board is divided into two parts--one for the connections
of the alternators to the bus bars and the other for the connection
of feeders to bus bars. The drawing on page 97 shows in plain view
the essential features of the control boards.
[Sidenote: _The
Instrument
Board_]
A front view of the Instrument Board is shown on page 97. This
board contains all indicating instruments for alternators and feeders.
It also carries standardizing instruments and a clock. In the
illustration the alternator panels are shown at the left and the
feeder panels at the right. For the alternator panels, instruments of
the vertical edgewise type are used. Each vertical row comprises the
measuring instruments for an alternator. Beginning at the top and
enumerating them in order these instruments are: Three ammeters, one
for each phase, a volumeter, an indicating wattmeter, a power factor
indicator and a field ammeter. The round dial instrument shown at the
bottom of each row of instruments is a three-phase recording
wattmeter.
A panel located near the center of the board between alternator panels
and feeder panels carries standard instruments used for convenient
calibration of the alternator and feeder instruments. Provision is
made on the back of the board for convenient connection of the
standard instruments in series with the instruments to be compared.
The panel which carries the standard instruments also carries ammeters
used to measure current to auxiliary circuits in the power house.
For the feeder board, instruments of the round dial pattern are used,
and for each feeder a single instrument is provided, viz., an ammeter.
Each vertical row comprises the ammeters belonging to the feeders
which supply a given sub-station, and from left to right these are in
order sub-stations Nos. 11, 12, 13, 14, 15, 16, 17, and 18; blank
spaces are left for four additional sub-stations. Each horizontal row
comprises the ammeter belonging to feeders which are supplied through
a given group switch.
This arrangement in vertical and horizontal lines, indicating
respectively feeders to given sub-stations and feeders connected to
the several group switches, is intended to facilitate the work of the
operator. A glance down a vertical row without stopping to reach the
scales of the instruments will tell him whether the feeders are
dividing with approximate equality the load to a given sub-station.
Feeders to different sub-stations usually carry different loads and,
generally speaking, a glance along a horizontal row will convey no
information of especial importance. If, however, for any reason the
operator should desire to know the approximate aggregate load upon a
group of feeders this systematic arrangement of the instruments is of
use.
[Illustration: SWITCHBOARD FOR ALTERNATING CURRENT BLOCK SIGNAL
CIRCUITS--IN SUB-STATION]
[Illustration: EXTERIOR OF SUB-STATION NO. 18]
[Sidenote: _Alternating
Current
Distribution
to Sub-Stations
Power House
Ducts and
Cables_]
From alternators to alternator switches the 11,000 volt alternating
currents are conveyed through single conductor cables, insulated by
oil cambric, the thickness of the wall being 12/32 of an inch. These
conductors are installed in vitrified clay ducts. From dynamo switches
to bus bars and from bus bars to group and feeder switches, vulcanized
rubber insulation containing 30 per cent. pure Para rubber is
employed. The thickness of insulating wall is 9/32 of an inch and the
conductors are supported upon porcelain insulators.
[Sidenote: _Conduit
System for
Distribution_]
From the power house to the subway at 58th Street and Broadway two
lines of conduit, each comprising thirty-two ducts, have been
constructed. These conduits are located on opposite sides of the
street. The arrangement of ducts is 8 x 4, as shown in the section on
page 96.
[Illustration: EXTERIOR OF SUB-STATION NO. 11]
The location and arrangement of ducts along the line of the subway are
illustrated in photographs on pages 98 and 99, which show
respectively a section of ducts on one side of the subway, between
passenger stations, and a section of ducts and one side of the subway,
beneath the platform of a passenger station. From City Hall to 96th
Street (except through the Park Avenue Tunnel) sixty-four ducts are
provided on each side of the subway. North of 96th Street sixty-four
ducts are provided for the West-side lines and an equal number for the
East-side lines. Between passenger stations these ducts help to form
the side walls of the subway, and are arranged thirty-two ducts high
and two ducts wide. Beneath the platform of passenger stations the
arrangement is somewhat varied because of local obstructions, such as
pipes, sewers, etc., of which it was necessary to take account in the
construction of the stations. The plan shown on page 98, however,
is typical.
The necessity of passing the cables from the 32 x 2 arrangement of
ducts along the side of the tunnel to 8 x 8 and 16 x 4 arrangements of
ducts beneath the passenger platforms involves serious difficulties in
the proper support and protection of cables in manholes at the ends of
the station platforms. In order to minimize the risk of interruption
of service due to possible damage to a considerable number of cables
in one of these manholes, resulting from short circuit in a single
cable, all cables except at the joints are covered with two layers of
asbestos aggregating a full 1/4-inch in thickness. This asbestos is
specially prepared and is applied by wrapping the cable with two
strips each 3 inches in width, the outer strip covering the line of
junction between adjacent spirals of the inner strip, the whole when
in place being impregnated with a solution of silicate of soda. The
joints themselves are covered with two layers of asbestos held in
place by steel tape applied spirally. To distribute the strains upon
the cables in manholes, radical supports of various curvatures, and
made of malleable cast iron, are used. The photograph on page 100
illustrates the arrangement of cables in one of these manholes.
[Illustration: OPERATING BOARD--SUB-STATION NO. 11]
In order to further diminish the risk of interruption of the service
due to failure of power supply, each sub-station south of 96th Street
receives its alternating current from the power house through cables
carried on opposite sides of the subway. To protect the lead sheaths
of the cables against damage by electrolysis, rubber insulating pieces
1/6 of an inch in thickness are placed between the sheaths and the
iron bracket supports in the manholes.
[Sidenote: _Cable
Conveying
Energy from
Power House to
Sub-Stations_]
The cables used for conveying energy from the power house to the
several sub-stations aggregate approximately 150 miles in length. The
cable used for this purpose comprises three stranded copper conductors
each of which contains nineteen wires, and the diameter of the
stranded conductor thus formed is 2/5 of an inch. Paper insulation is
employed and the triple cable is enclosed in a lead sheath 9/64 of an
inch thick. Each conductor is separated from its neighbors and from
the lead sheath by insulation of treated paper 7/16 of an inch in
thickness. The outside diameter of the cables is 2-5/8 inches, and the
weight 8-1/2 pounds per lineal foot. In the factories the cable as
manufactured was cut into lengths corresponding to the distance
between manholes, and each length subjected to severe tests including
application to the insulation of an alternating current potential of
30,000 volts for a period of thirty minutes. These cables were
installed under the supervision of the Interborough Company's
engineers, and after jointing, each complete cable from power house to
sub-station was tested by applying an alternating potential of 30,000
volts for thirty minutes between each conductor and its neighbors, and
between each conductor and the lead sheath. The photographs on
page 98 illustrates the construction of this cable.
[Sidenote: _Sub-Station_]
The tri-phase alternating current generated at the power house is
conveyed through the high potential cable system to eight sub-stations
containing the necessary transforming and converting machinery. These
sub-stations are designed and located as follows:
[Illustration: DIAGRAMS OF DIRECT CURRENT FEEDER AND RETURN CIRCUITS]
Sub-station No. 11--29-33 City Hall Place.
Sub-station No. 12--108-110 East 19th Street.
Sub-station No. 13--225-227 West 53d Street.
Sub-station No. 14--264-266 West 96th Street.
Sub-station No. 15--606-608 West 143d Street.
Sub-station No. 16--73-77 West 132d Street.
Sub-station No. 17--Hillside Avenue, 301 feet West of
Eleventh Avenue.
Sub-station No. 18--South side of Fox Street (Simpson
Street), 60 feet north of Westchester Avenue.
[Illustration: SWITCH CONNECTING FEEDER TO CONTACT RAIL]
[Illustration: CONTACT RAIL JOINT WITH FISH PLATE]
The converter unit selected to receive the alternating current and
deliver direct current to the track, etc., has an output of 1,500
kilowatts with ability to carry 50 per cent. overload for three hours.
The average area of a city lot is 25 x 100 feet, and a sub-station
site comprising two adjacent lots of this approximate size permits the
installation of a maximum of eight 1,500 kilowatts converters with
necessary transformers, switchboard and other auxiliary apparatus. In
designing the sub-stations, a type of building with a central air-well
was selected. The typical organization of apparatus is illustrated in
the ground plan and vertical section on pages 101, 102 and 103 and
provides, as shown, for two lines of converters, the three
transformers which supply each converter being located between it and
the adjacent side wall. The switchboard is located at the rear of the
station. The central shaft affords excellent light and ventilation for
the operating room. The steel work of the sub-stations is designed
with a view to the addition of two storage battery floors, should it
be decided at some future time that the addition of such an auxiliary
is advisable.
[Illustration: CONTACT RAIL BANDS]
The necessary equipment of the sub-stations implies sites
approximately 50 x 100 feet in dimensions; and sub-stations Nos. 14,
15, 17, and 18 are practically all this size. Sub-stations Nos. 11 and
16 are 100 feet in length, but the lots acquired in these instances
being of unusual width, these sub-stations are approximately 60 feet
wide. Sub-station No. 12, on account of limited ground space, is but
48 feet wide and 92 feet long. In each of the sub-stations, except No.
13, foundations are provided for eight converters; sub-station No. 13
contains foundations for the ultimate installation of ten converters.
[Illustration: DIRECT CURRENT FEEDERS FROM MANHOLE TO CONTACT RAIL]
The function of the electrical apparatus in sub-stations, as has been
stated, is the conversion of the high potential alternating current
energy delivered from the power house through the tri-phase cables
into direct current adapted to operate the motors with which the
rolling stock is equipped. This apparatus comprises transformers,
converters, and certain minor auxiliaries. The transformers, which are
arranged in groups of three, receive the tri-phase alternating current
at a potential approximating 10,500 volts, and deliver equivalent
energy (less the loss of about 2 per cent. in the transformation) to
the converters at a potential of about 390 volts. The converters
receiving this energy from their respective groups of transformers in
turn deliver it (less a loss approximating 4 per cent. at full load)
in the form of direct current at a potential of 625 volts to the bus
bars of the direct current switchboards, from which it is conveyed by
insulated cables to the contact rails. The photograph on page 102
is a general view of the interior of one of the sub-stations. The
exterior of sub-stations Nos. 11 and 18 are shown on page 107.
[Illustration: CONTACT RAILS, SHOWING END INCLINES]
The illustration on page 108 is from a photograph taken on one of
the switchboard galleries. In the sub-stations, as in the power house,
the high potential alternating current circuits are opened and closed
by oil switches, which are electrically operated by motors, these in
turn being controlled by 110 volt direct current circuits. Diagramatic
bench boards are used, as at the power house, but in the sub-stations
they are of course relatively small and free from complication.
The instrument board is supported by iron columns and is carried at a
sufficient height above the bench board to enable the operator, while
facing the bench board and the instruments, to look out over the floor
of the sub-station without turning his head. The switches of the
direct current circuits are hand-operated and are located upon boards
at the right and left of the control board.
A novel and important feature introduced (it is believed for the first
time) in these sub-stations, is the location in separate brick
compartments of the automatic circuit breakers in the direct current
feeder circuits. These circuit breaker compartments are shown in the
photograph on page 93, and are in a line facing the boards which
carry the direct feeder switches, each circuit breaker being located
in a compartment directly opposite the panel which carries the switch
belonging to the corresponding circuit. This plan will effectually
prevent damage to other parts of the switchboard equipment when
circuit-breakers open automatically under conditions of short-circuit.
It also tends to eliminate risk to the operator, and, therefore, to
increase his confidence and accuracy in manipulating the hand-operated
switches.
[Illustration: ASSEMBLY OF CONTACT RAIL AND PROTECTION]
The three conductor cables which convey tri-phase currents from the
power house are carried through tile ducts from the manholes located
in the street directly in front of each sub-station to the back of the
station where the end of the cable is connected directly beneath its
oil switch. The three conductors, now well separated, extend
vertically to the fixed terminals of the switch. In each sub-station
but one set of high-potential alternating current bus bars is
installed and between each incoming cable and these bus bars is
connected an oil switch. In like manner, between each converter unit
and the bus bars an oil switch is connected into the high potential
circuit. The bus bars are so arranged that they may be divided into
any number of sections not exceeding the number of converter units, by
means of movable links which, in their normal condition, constitute a
part of the bus bars.
Each of the oil switches between incoming circuits and bus bars is
arranged for automatic operation and is equipped with a reversed
current relay, which, in the case of a short-circuit in its
alternating current feeder cable opens the switch and so disconnects
the cable from the sub-station without interference with the operation
of the other cables or the converting machinery.
[Illustration: CONTACT RAIL INSULATOR]
[Sidenote: _Direct Current
Distribution
from
Sub-Stations_]
The organization of electrical conductors provided to convey direct
current from the sub-stations to the moving trains can be described
most conveniently by beginning with the contact, or so-called third
rail. South of 96th Street the average distance between sub-stations
approximates 12,000 feet, and north of 96th Street the average
distance is about 15,000 feet. Each track, of course, is provided with
a contact rail. There are four tracks and consequently four contact
rails from City Hall to 96th Street, three from 96th Street to 145th
Street on the West Side, two from 145th Street to Dyckman Street, and
three from Dyckman Street to the northern terminal of the West Side
extension of the system. From 96th Street, the East Side has two
tracks and two contact rails to Mott Avenue, and from that point to
the terminal at 182d Street three tracks and three contact rails.
[Illustration: CONTACT SHOE AND FUSE]
Contact rails south of Reade Street are supplied from sub-station No.
11; from Reade Street to 19th Street they are supplied from
sub-stations Nos. 11 and 12; from 19th Street they are supplied from
sub-stations Nos. 12 and 13; from the point last named to 96th Street
they are supplied from sub-stations Nos. 13 and 14; from 96th Street
to 143d Street, on the West Side, they are supplied from sub-stations
Nos. 14 and 15; from 143d Street to Dyckman Street they are
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