Chapter 03. General Arrangement for Construction

The New York Rapid Transit Railway Extensions · Engineering News, 1914

The Operating Contracts. Stated briefly, the original contracts for the present subway provided for its construction by the city or with the city's money, its equipment of power stations, electrical apparatus, signals, telephones, rolling stock, etc., being furnished by the operating company, which had a lease for 50 years, with privilege of renewal for 25 more. Contract 2, Brooklyn extension, 35 years and 25 years. These two contracts with the renewals would, therefore, run to 1979 and 1965, respectively. The operating company was to pay a rental sufficient to cover the interest and amortization on the bonds issued by the city in payment of the cost of construction. At the end of the lease, the city to own the structure free and clear, with the right to purchase the equipment.

The elevated lines in Manhattan have a perpetual franchise, so that under the new arrangement, the lease for the extensions to these lines and the third tracks was made to run for 85 years, and is not included in the agreement covering the other lines, which is as follows:

By the terms of the new contracts, the leases of all the new lines as well as those of the existing subway are to run for 49 years from Jan. 1, 1917, and provide that the city shall share in the profits of operation, which are to be determined in tile following manner:

The revenues of all operated lines of each system will be pooled, the two companies will be allowed to retain all the earnings (after payment of rentals, interest, amortization, etc.) on the lines they now operate, and the city will share in the profits of the rest. The contracts provide for quarterly settlements, which will provide for the following payments:

[The text describing the payment schemes was quoted verbatim from New Subways for New York: The Dual System of Rapid Transit, Chapter 5: Terms and Conditions of Dual System Contracts, section "Terms of the Lease."--Ed.]

Route and Section Numbers.

The custom was established in the days of the old Rapid Transit Commission of assigning a number to the various different routes proposed from time to time for new lines, and this has been perpetuated, as, for instance, the Lexington Ave. route is Route 5, etc. It seems hardly necessary, however, for the purpose of these articles to enumerate these in detail.

For construction purposes, each route is divided into sections, numbered consecutively from the south toward the north in Manhattan and the Bronx, from west to east in Brooklyn. The sections vary considerably in length but are generally about half a mile, and the bids so far obtained range from about $800,000 to $4,000,000 per section. The cost of structure and per foot of track is shown in the accompanying table, which also shows the per cent. of work completed on each section on Mar, 1, 1914, and the names of the contractors. The prices given in this table do not include station finish, such as tiling, stairways, ticket offices, railing, etc., or any track or equipment.

Fig. 7. Profile of the Lexington Avenue Line. (Click image to enlarge.)

There is very little comment which can be made on these figures. The work is so varied that there is, as will be seen, a wide variation in the prices either per lin.ft. of track or per lin.ft. of structure. The Lexington Ave. line is perhaps fairly typical of normal conditions. (See profile, Fig. 7.) From 53rd St. to 129th St. the price is fairly uniform at about $225 per lin.ft. of track. Sections 9 and 10, however, have two tracks in tunnel which can be built with little or no interference with subsurface structures and no street support, and this is reflected in the lower price. Section 13 has a high price per lin.ft. of structure, as this, it will be noted later, provides for a very elaborate system of track crossings. Section 14 is the Harlem River crossing. The sections north of the Harlem, Route 5, Section 15, Routes 19 and 22, Sections 1 and 1a, where only part of the street is required to be decked and where the streetcars are operated by the overhead trolley, show a considerable decrease in the cost per lin.ft., as do also the elevated structures on Jerome Ave. and White Plains Road.

On the downtown lines, Route 5 (Broadway), Section 1 involves the support of the elevated railroad structure; Section 1a the two reversed curves driven in tunnel; Section 2a the crossing of Canal St., where the underground conditions are very bad. The other sections, which are perhaps more nearly normal, show approximately an approach to the commonly accepted rough estimate figure of $1,000,000 per mile of track, built in subway.

Fig. 8. Typical section of rapid transit subway on Seventh Avenue at 23rd Street. (Click image to enlarge.)

Equipment. There has been no announcement so far of any change in the type of rolling stock of the Interborough, but the B.R.T. has had a larger type of car designed, Fig. 9, providing considerably greater capacity which will, it is thought, owing to the arrangement of the doors, permit such easy ingress and egress that there will be no more delay in loading and unloading than there is with the small cars now in use. The principal dimensions of these two cars are as follows:

There have been many difficulties to overcome in connection with the design of these larger cars. Axle loads of 31,000 lbs. cannot be exceeded, as this is fixed by the bridge department for the East River bridges. The motors are arranged one on each truck, instead of both on one truck, as on the present Interborough car, this, of course, giving a better distribution of the weight and taking care of some of the increase in the weight of the body and number of passengers. The limitation as to the axle loadings could not be overcome by the adoption of six-wheeled trucks, even though their use were not prohibited by the sharp curvature, as this would only involve a heavier truck with practically the same concentration of load so far as the bridge structures are concerned.

Some important improvements are to be introduced in the equipment of the cars. The combined car and air-line couplers (described in Engineering News, Feb. 29, 1912) have proven very satisfactory, and in addition to these couplers a device is to be installed in the new equipment which will also permit the automatic coupling of the electrical connections (10 in all). The coupling and uncoupling will be entirely under the control of the motorman and be governed by an interlocking device so that the electrical connection cannot be made until the air-line coupling is complete and the brakes are under control. Similarly to uncouple, the release of the electrical connection by the motorman permits him to release the devices so that the air and train couplings will part. It is hoped by these devices to materially decrease the number of accidents to men uncoupling cars, and also to reduce the time and expense of making up trains.

Fig. 9. Design for the steel car for the Brooklyn Rapid Transit system. (Click image to enlarge.)

Before the introduction of this automatic coupler the link-and-pin type had been in general use, but even with eight-car trains on the Interborough, the breaking in two of the trains was frequent enough to show that the limit had been reached for this type of couplings. Automatic stops in connection with the signals are in use in the present subway, and the sudden setting of the brakes produces heavy stresses on the couplings. The new coupler has satisfactorily stood all the strains due to these causes, and the introduction of 10-car trains made it almost an absolute necessity. Electric pneumatic brake control will be used on the new equipment, insuring more nearly simultaneous action of the brakes on all the cars.

The signal to the motorman is given by the closing of an electric circuit when all the doors of the train are closed. This has been in use successfully for some little time already, and not only saves the delay due to transmitting the signal from car to car by hand, but also acts as a safety device in preventing the starting of the train while any door is open.

A species of weighting device has been introduced in connection with the air-line system to maintain the same ratio of breaking power on loaded and empty cars. As the car is stopped at the station, the variation in the load due to the discharge or receipt of passengers, actuates a piston in an auxiliary air cylinder, directly connected to the jam-cylinder. The variation in the position of this piston in the auxiliary cylinder regulates the volume of the jam cylinder, thereby regulating the effective pressure obtained from a given amount of air; thus when the car is fully loaded the volume of the auxiliary cylinder is at its minimum, and when the car is empty it is at its maximum. When the doors are closed it is automatically locked this position until they are opened at the next station, thus preventing any change from variations in the loading due to the vibration and oscillation of the moving train.

A similar device is to be applied to the accelerating system. At present this has to be adjusted so that it will not slip the wheels of an unloaded car. With the proposed device, however, it will be so adjusted that it will be increased under load.

By these various devices it is expected to save six minutes in time between 59th St. and Coney Island. Deceleration from 50 miles per hour will be accomplished at the rate of 3 mi. per hr. per sec. (on the emergency) as compared with the present maximum of 2 mi. per hr. per sec. and from the lower rates of speed at higher rates of deceleration, while acceleration will be at the rate of 1.5 mi. per hr. per sec.

Comparison of this with some comparatively recent practice on the electrified steam railroads is of interest:

N.Y., N.H., & H. R.R.: Multiple unit trains 1 motor 2 trailers, acceleration 0.5 mi. per hr. per sec. Schedule speed from Grand Central Station to Mt. Vernon, 13.5 miles, with 1 stop, in 28 minutes.

Lancashire and Yorkshire R.R., England: Acceleration to 30 mi. per hr. in 30 sec. Schedule speed, 18.5 miles with 14 stops in 37 minutes.

Power. Power for the Interborough system is to he furnished from the power houses at 59th St. and the North River and at 74th St. and the East River. The former, built to furnish power for the present subway, was originally equipped with nine reciprocating units with a total normal capacity of 7,500 kw. each. This was increased later by the addition of five low-pressure turbines each having an additional capacity of 7,500 kw. and using exhaust steam from the original units to a total of 105,000 kw. This plant is now to be enlarged by the addition of two 30,000-kw. turbine units, each unit consisting of a high-pressure high-speed set exhausting into a low-pressure low-speed turbine, making the total normal capacity about 165,000 kw.

The 74th St. power house was built only 13 years ago when the elevated lines were electrified, but owing to the rapid change and improvement which is continually taking place in electrical machinery and apparatus, part of this plant is to be replaced. The old equipment consisted of eight units (reciprocating) and one turbine unit of 7,500 kw. each. Four of these are to be taken out and three turbine generators of 30,000 kw. each are to be installed, which, with the five old units remaining, will make a total normal capacity of 127,500 kw.

The contracts between the operating companies and the city call for an average speed on express tracks between main-line terminals of 25 miles per hour, including stops of 30 seconds at each intermediate station, and an average speed on local tracks between terminals of 15 miles per hour, including stops of 20 seconds at each intermediate station.

Gradients and Alignment.

Unlike the location of steam railroads, the location of such lines as these under consideration is governed only to a comparatively small extent by questions of gradient or alignment as they affect economy of operation. The primary consideration, of course, is the general location of the lines through or under streets in those sections of the city where service is needed. The second consideration is the location of the various stations, which, in the lower part of Manhattan (below 42nd St.) are about five or six blocks (1200 to 1300 feet) apart, and in the outlying sections about 2500 ft. apart, and which is arbitrarily fixed by local conditions. Then the grades and alignment (within certain fairly wide limits) are made to fit these conditions. At present, owing to the fact that some sections of the line are not definitely designed, it is not possible to make an exact and complete statement covering the gradients and alignments of the whole system but the following is approximately correct.

Gradients. Gradients up to 3% may be considered normal, this upper limit being used with considerable frequency, though generally in comparatively short stretches. Some of the longest are nearly 1500 ft. in length, and in a very few cases 3% grades, as long as this occur as ascending grades immediately beyond a station stop on the local lines. There are gradients in excess of this up to 4.5%, and in one case where the Centre Street Loop connects to the old Brooklyn Bridge it has been necessary to use 5.4%. [This connection was never finished. --Ed.] The higher rates of gradient occur mostly in connection with the approaches to the East River Bridges or the tunnels under the rivers, the grades of the former being 3.4% on the three newer bridges and 3.75% on the old Brooklyn Bridge.

With electrical operation and especially with the dense traffic conditions which exist or which will exist on the rapid transit lines in New York, the question of gradients is not so important as it is in connection with the locations of railroad lines for operation by steam locomotives, or where continuous sustained effort is required on long supported gradients.

For short sections of heavy grade, extra power is supplied through an additional feed wire, or wires to the points where it is needed. The electric motor as is known can stand a heavy overload of as much as 100%, or even more for short periods, the amount of the load and the time which it can be carried being limited by the heating which takes place under these conditions. Short stretches of steep gradient are not, therefore, limiting or as important as longer ones would be. Considering the requirements for some reserve power for ordinary operation which have to be fairly liberal, on account of the great seriousness of any delay as well as the short distance between stations, it can be seen that the limits controlling the gradients which may be used are rather wide.

In the operation of self-contained motor cars also, there is the advantage over trains hauled by locomotives that all additional load increases the adhesion and, therefore, permits application of the power neeessary to haul it. It may also be noted that the new motors are to be artificially cooled by blowers.

The general procedure has been that the gradients are fixed by local conditions within the limits given above, then the motors are designed to carry the load. Momentum is availed of wherever possible, where under normal conditions trains may be expected to utilize it in overcoming ascending gradients, and this can quite safely be done, because in case a train is stopped on an upgrade, the motors can he relied to start it and move it along, even though at low speed, on account of their great capacity for overload. The original subway equipment was designed on a basis of 60% motors and 40% trailers, but the tendency is toward the equipment of all cars with motors.

On the underground lines so far as possible, stations have been located at summits of gradients, both in order to get them as near the surface as possible and also that the ascending gradient may be utilized in braking, and the descending gradient to aide in acceleration. While, however, these two practices mutually help each other on the subway lines, and the rise and fall involved is, therefore, not an operating expense, this is not the case on the elevated lines. These latter, of course, must maintain a certain minimum elevation over summits, but the comparatively slight additional cost of longer columns is so little, that there is every inducement to avoid dipping down into depressions even, or perhaps especially, if stations happen to be located at such points, and it has seemed better to put in escalators or elevators than to drop the track grade down, involving braking on a descending grade and acceleration against an opposing grade.

In other instances at least, on the original subway (at 33rd St. and Park Ave.) on the four-track section, the two center tracks, which are used for the expresses, are carried through on an even grade, while the outer two local tracks are raised up at the stations. On the new lines the tracks generally all follow the same grade except on Lexington Ave., where the express tracks are located on a lower grade in tunnel through the hill; but here, on account of the necessity of having an express stop at some point as nearly as possible midway between 42d St. and 125th St., it was necessary to bring the express tracks up near the surface at 86th St., as shown in the profile, Fig. 7, which is very typical of the way local conditions absolutely control the profile. From an operating standpoint, of course it would have been much better to have run all the way through the hill on the lower grade.

On account of the capacity of the electric motor for overload also, there is little necessity for, or benefit to be derived from, the compensation of grades for curvature, although it is not uncommon to find the heavier rates of gradient combined with quite sharp curvature, as for instance, at Vesey St. and Broadway, where there is a 4% grade on a curve of 200 ft. radius.

By reference to the profile of the original subway line (Eng. News, Feb. 20, 1902) it will be seen that much steeper gradients have been found necessary on the new routes than are used on the present line, but this, as is explained above, has virtually been forced by the conditions which have had to be met, which are more onerous in many cases on the new routes than on the old.

On the old line, the Broadway section has no gradient in excess of 1.5%, and the Bronx branch has 3% grades only at the crossing of the Harlem River and 2.2% just beyond where the line comes out on to the elevated structure.

In a way, the profile given, Fig. 7, of the Lexington Ave. line from 40th St. to 138th St. may be considered fairly typical, though on the other hand, the Varick St.-Seventh Ave. line from the Battery to 42d St. has light grades throughout its length, comparing favorably with the old line, with which it will connect at 42nd Street.

Alignment. The alignment, of course is governed by the same considerations of the necessity of following the streets, and so far as possible, avoiding encroachment on private property. This is especially difficult in the lower part of Manhattan, where the streets are narrow and crooked, and where it is especially difficult to turn the curves, so that in some instances, notably at St. Paul's churchyard, at Vesey St. and Broadway, and also at 42nd St. and Lexington Ave., it has been necessary to acquire easements under private property at considerable expense. On the new lines all stations are to be located on tangents, to avoid the difficulties found on the original subways with stations on curves.

On the present subway in which cars 51 ft. long and 9 ft. 0.5 in. wide are operated, there are the following sharp curves:

The outer rails on curves were elevated for speeds of 30 miles per hr. with a maximum of 6.5 in., and this practice is followed in designing the new lines, though in some cases the operating company has increased the elevation in the old subway to permit speeds of 40 mi. per hr., on some of the curves of large radius.

On the new lines 500 ft. has been considered the minimum radius for ordinary cases, 200 ft, the absolute minimum, except that there is one curve of 150 ft. radius. On the B. R. T. lines additional clearance has to be provided on curves to provide for the extra overhang of the larger cars, 67 ft. long and 10 ft. wide, which that company proposes to use.

Transition curves of a uniform length of 150 ft., irrespective of the degree of curvature are used, wherever it is possible to get them in. Crandall's formulas and tables are used. It may be noted that curves are usually laid out with radii of even feet instead of with even degrees of curvature.

Contracts and Specifications.

General Clauses. The clauses of the specifications indicating the character of the work to be performed under each item or type of construction, will be discussed or quoted under each separate heading, together with the descriptions of the work. The general clauses of the contract and specifications where they differ from ordinary practice, or where they have particular applications on this work are briefly noted below.

The contracts are printed in pamphlet form, letter-size sheet (8x11). There is a table of contents at the beginning and a complete index at the end. Plans were published originally on large sheets about 22x30, lithographed and bound together, but this has been changed for smaller-sized plans which are lithographed on thin paper uniformly 11 in. wide, and bound into letter size (8x11) pamphlets the same as the contracts, thus making them very easy and convenient to handle.

The contracts for the general construction do not include any station finish of any kind, nor the track, ballast, or electrical equipment except such parts as necessarily have to be incorporated in the main structure, such as conduits for electric wiring, power cables. etc., and the ducts or pipes for lighting wires at the stations. The automatic pumps at the pumping stations are included as, of course, the drainage has to be taken care of from the beginning. The contract drawings usually include enough plans showing the general scheme of station finish, so that the contractor will have this as a guide in carrying out his work and that he may make due allowances for it. All necessary changes in location of sewers, water and gas pipes, electrical conduits, etc., required by the construction of the of the subway are included in the contract, the principal changes of the larger structures are shown on the plans, but exact details of smaller pipes, conduits, etc., are left until the existing pipes are uncovered, and all subsurface structures definitely and exactly located.

Approximate quantities of each item are given for the purpose of comparing the bids on a basis of total cost. The time may be extended or diminished if there is any material change in total quantities.

There are provisions calling special attention to the necessity of compliance with state and city laws, especially the eight-hour law and the requirement that contractors shall pay the union scale of wages.

As the work is to a large extent to be carried out in residential districts, there are provisions which give the engineers adequate control of night work of any kind which might disturb people living near the line. Blasting is not permitted between the hours of 11 p.m. and 7 a.m. There are strict provisions (regular city ordinance) for the storage of explosives, the maximum capacity in any magazine being 250 lb., and in most of them not over 100 lb.

Bond. A certified check for a stated sum, varying from $10,000 to $25,000, according to the size of the contract, is required with all proposals and a bond of a stated sum of approximately 10% of the amount of the contract from the accepted contractor, 15% is retained from the monthly payments up to a total of about 10% of the amount of the contract, after which only 10% is deducted.

Time. The following clause is of interest in the provision for completion within the specified time: "In the event of delay.... the city.... shall be paid damages for such delay. Inasmuch as the amount of such damages will be extremely difficult to ascertain, especially in view of the fact that the railroad here contracted for is only a part of a complete system, the remainder of which is to be constructed under other contracts, it is hereby expressly agreed that damages shall be liquidated and paid by reducing the price to be paid the contractor as follows:"

The provision then is for the retention of 1% of the amount due for the work done in the first month, after the time elapses, 2% for the second month, and so on.

The following "blanket" clause is of interest in connection with works of large magnitude, where the subsurface conditions are as uncertain as they may be in a city:

"The specifications and contract drawings hereinafter mentioned and taken in connection with the other provisions of this contract, are intended by the Commission to be full and comprehensive, and to show all the work required be done. But in a work of this magnitude it is impossible either in advance to show all details, or precisely to forecast all exigencies. The specifications and contract drawings are to be taken, therefore, as indicating the amount of work, its nature and the method of construction so far as the same are now distinctly apprehended. The railroad is intended to be constructed for actual use and operation as an intraurban railroad of the highest class, adapted to the necessities of the people of New York, in the best manner, according to the best rules and usages of railroad construction, and in the event of any doubt as to the meaning of any portion or portions of the specifications or contract drawings, or of the text of the contract, the same shall be interpreted as calling for the best construction, both as to materials and workmanship, capable of being supplied or applied under the then existing local conditions. All the clauses of the specifications, and all the parts of the contract drawings are, therefore, to be understood, construed and interpreted as intending to produce the results hereinbefore stated."

Monthly Estimates. "The engineer shall make an estimate of the amount and value of the work done as in his opinion shall be just and fair, but shall not necessarily be governed by the unit prices contained in the contractors' proposal, and provided that such estimate shall be withheld or reduced if in the opinion of the engineer the work is not proceeding in accordance with the contract."

An allowance is made for structural steel delivered, at the rate of $40 per ton.

The contracts provide that the city shall make payments on estimates within 30 days after a certificate is issued by the Commission. As a matter of fact, payments are usually made within 30 days of the end of the month covered by each estimate. Final payments are to be made 90 days after the filing of a certificate of completion.

Shafts and Openings. Plans showing the location of all shafts, plant to be erected in the streets, supports of decking, openings in decking, must be submitted to the engineers, and receive their approval before work is commenced. This of course, in addition to the regular permits to be obtained from the city.

Liability. The contractor admits (under the form of contract) that if the work be done without fault, or negligence on his part that the plans, etc., do not involve any danger of foundations, walls, or other parts of adjacent buildings) etc.