Loading Speed A Major Factor in Design of New York Subway Cars (1931)
Electric Railway Journal · Vol. 75, No. 6 · June 1931 · pp 294-297.
Four wide double doors on each side make for quick passenger interchange in this 60-ft. car designed by the Board of Transportation.
Loading Speed a Major Factor in Design of New York Subway Cars. Board of Transportation develops rapid transit car of improved type for use on new city-owned lines. Many advances have been made over existing designs.
When the Board of Transportation perfected its plans for the new subway system authorized for New York City, a change from the previous procedure was deemed necessary. In the former contracts the operating companies leased the bare subways built by the city and themselves provided the necessary equipment, including cars, power and miscellaneous apparatus. On account of uncertainty as to the arrangement under which the new lines will be operated, it became necessary for the city to provide the complete equipment in order to avoid serious delay in starting service.
Accordingly, the design of the cars was undertaken by the Board of Transportation. At the request of the board, J. S. Doyle of the Interborough Rapid Transit Company, W. G. Gove of the Brooklyn-Manhattan Transit Corporation, W. B. Potter of the General Electric Company, A. E. Ostrander of the American Car & Foundry Company, and W. H. Mussey of the Pullman Company, along with H. N. Latey and J. O. Madison, served as a committee regarding the best type of car for the subway service. During the six months this committee deliberated some 75 different arrangements were considered and analyzed. While it was not possible to obtain a unanimous opinion in favor of any one type of car, it was agreed that the car decided on by the board will be an effective transportation unit.
Three distinct types of rolling stock are in use on the existing rapid transit subway lines in New York City. The cars of the Interborough subway are approximately 51 ft. long and 9 ft. wide, while the standard B.M.T. subway cars are 67 ft. long and 10 ft. wide. The three-unit articulated cars of the B.M.T. are 137 ft. long and 10 ft. wide. The clearances adopted in the new subways make them suitable for the B.M.T. cars. Accordingly, in most of the principal dimensions those of the latter were followed in the design of the new cars. The two types can use the same tracks and the same station platforms. While the differences in control and electrical equipment prevent operating them interchangeably, they can be coupled together in emergencies.
It was decided that better service could be rendered by making the maximum length of the new car 60 ft. instead of 67 ft. as in the B.M.T. car. This made it possible to place the truck centers nearer the ends of the cars, reducing overhang and end swing and permitting a somewhat lighter framing. It also allows passengers to pass from one car to the next without danger, even on curves. It was decided to build single units, each with two motors on one truck, making all the cars interchangeable, in order to obtain maximum flexibility of service.
In selecting the type of car a study was made of the various elements limiting the number of trains per hour, as this determines the capacity of the line. Accelerating and braking rates were set at 1.75 m.p.h.p.s., which with the present type of control was believed to be as high as possible without discomfort to the passengers. Closing-in signals are provided at all congested points, so that no further material saving could be made in the time of entering or leaving stations. Hence, the limiting condition in the passenger capacity of the subway was determined to be the length of station stop.
With operation of about 30 trains per hour, which is approximately the maximum in the existing subways, it is evident that the saving of four seconds per train in the time of stop increases the capacity of the track by one train per hour. In order to determine how the maximum saving in stopping time can be obtained, studies of station stops were made at the most congested subway stations in New York, and many observations were made of the speed of loading and unloading. It was found that all of the- present cars have their doors so located that the natural distribution of traffic between them is unequal. In the Interborough cars more passengers use the center doors than either of the end doors. In the long B.M.T. cars the end doors have the heavier traffic. By equalizing the door zones the number of passengers boarding and leaving should be about the same at all doors, and the time of interchange reduced.
The new car was so designed that one-fourth of the load will be in the zone of each of the four side doors provided. The seat arrangement also was selected with a view to directing passengers toward the nearest door. Though it would be possible to increase the number of doors on each side of the car beyond the four actually adopted, it would result in a serious reduction in the number of seats if a normal arrangement is used. As a compromise between maximum track capacity and number of seats the four-door unit 60 ft. long and seating 60 passengers was adopted.
Double doors will open or close in about half the time needed with a single 4-ft. door. The lighter door will reduce the blow should it strike a passenger standing in the doorway. Flexible edges have been installed on the doors, and their width at the bottom is increased by notching out the door sufficiently that a man's foot may be withdrawn after the door is fully closed. This feature obviates the need for the "sensitive edges" used on some of the subway car doors. It also was decided to keep the door openings free of posts or divisions of any kind, as these reduce the capacity of the door.
The multiple-unit control practically removes any limitation as to train length. The public, however, demands stations fairly close together, which makes operation of long trains difficult. It was decided that all interests would be served best by the use of trains of ten 60-ft. cars, and the station platforms were designed accordingly, with provisions for lengthening them to accommodate eleven cars if that becomes desirable in the future.
Comparing the standard trains for subway service, ten cars of the Interborough type, eight cars of the B.M.T. 67-ft. type, or ten cars of the new Board of Transportation type, it was found that the number of trains per hour which can be moved through the most congested stations, and the resultant passenger capacity are, respectively:
|Trains per hour||29.7||30.7||32.2|
|Maximum passengers per car||200||300||280|
|Maximum cars per train||10||8||10|
|Passengers per train||2,000||2,400||2,800|
|Passengers per hour||59,400||73,400||90,160|
Thus the new car will permit an increase in train capacity above the I.R.T. equipment, due to the door arrangement, and an increase in hourly capacity from all causes that in the aggregate amounts to about 50 per cent.
Since car weight affects operating costs directly, every effort has been made to hold it down. The final scale weight for the car is 84,300 lb., as compared with the 85,000 lb. specified. This weight is relatively low for a 60-ft. long, 10-ft. wide car with two 190-hp. motors, automatic car, air and electric couplers, air brakes, and four double doors on each side of the car.
Each specialty manufacturer contributed to the weight reduction. A portion of the saving in weight was made by the use of aluminum, which is found in the doors, door devices, seat boxes, parts of the headlining, trim, cab construction, and some of the junction boxes and miscellaneous parts. The total saving in weight amounts to some 2,700 lb. per car. A comparatively new weight-saving feature was the use of thin wall conduit. Its internal diameter is the same as that of standard conduit, but the walls are only 1/16 in. thick. Threadless fittings facilitate installation. This was particularly true with bent sections, and some lengths of conduit could be placed in locations that would have been practically out of the question with screw fittings.
The complete car weighs 1,395 lb. per running foot when empty. With a full load of 280 passengers (39,200 lb.) the weight is 2,041 lb. per runing foot. The weight per seated passenger is 1,545 lb., and per total passenger at full load it is 441 lb.
The trucks are of the A.C.F. pedestal type. All members except the pedestals, journal boxes, transom gussets, side frame and bolster center castings, which are cast steel, are rolled bar or structural shapes and plates. Coil springs mounted on the journal boxes are high silicon steel and elliptic springs are chrome vanadium. The motor truck has a wheelbase of 7 ft. and the trailer truck 6 ft. 3 in.
Westinghouse Traction Brake Company H-2-A couplers are used, as are Westinghouse air brakes, with 18 x 12-in. cylinders. Variable load mechanism provides for a standard rate of retardation and acceleration irrespective of the number of passengers on the car. The cars have automatic slack adjusters on the brake cylinders, and the motor trucks have shim slack adjusters. Both motor and trailer trucks have Simplex clasp brakes and Diamond S brakeshoes.
Each car is driven by two Westinghouse No. 570-D-5, 190-hp. field control motors. Westinghouse ABF electropneumatic control makes it possible to run a train of from one to eleven cars from a single position. Control is of the automatic battery field type, with acceleration set at the rate of 1.75 m.p.h.p.s. There also is a variable load feature for the accelerating relays, so that the rate of acceleration is maintained regardless of load. The operating coils of the line switch are actuated with trolley current, so that the main motor circuit is opened immediately on loss of power, but the multiple-unit control is operated from a low-voltage storage battery. This simplified the design of the control apparatus, provided a means for easy testing of the control without the use of power from the line and causes all the high-voltage circuits to be interrupted under the floor of the car.
Good lighting of the car interior is obtained from 22 Mazda C Type A-21 automatic cutout lamps in series, each lamp taking 1.6 amp. at 30 volts. These are set in short-circuiting sockets. White enameled stanchions are so placed as to support standing passengers who cannot reach the enameled hand straps.
Four battery emergency lights per car go on if the power is off the line. Each car has an Edison 24-cell Type B-4-H battery, regulated automatically by a charging panel, which allows the battery to charge in series with the compressor motor, or, if this rate is not sufficient, directly from the third rail through a resistance.
The car lamps, heaters, ventilating fans and destination signs have their circuits so arranged that they can be controlled from the tnotorman's position at the head of the train, for all eleven cars, the maximum number contemplated, or less. The destination signs on the ends of the trains are adjusted by the motorman and once set for a particular line are not changed during the run. Side destination signs are set for the particular run, but the designation of the terminal toward which the train is proceeding is illuminated in color and is changed from one direction to the other by the setting of the motorman's reverser key. Besides the end destination signs which give the route number and destination in large illuminated characters, red and green illuminated signs on each side of the end of the train show whether it is a local or an express.
The door control is arranged for multiple-unit operation, the front half of the train, up to a maximum of six cars, being controlled by the conductor, and the rear half, of five cars or less, by the guard.
A safety feature embodied in the door control consists in having the electropneumatic door locks controlled by a separate circuit from that of the door opening and closing mechanism.
Twenty-six train line wires through the electric couplers carry battery current for control of motors, brakes, door engines, lamps, fans, heaters and destination signs.
The design, inspection and tests of the cars and their equipment have been done in the engineering department of the Board of Transportation, of which Robert Ridgway is chief engineer, J. R. Slattery, deputy chief engineer, H. N. Latey chief electrical engineer, and John O. Madison engineer of cars and shops. The latter was in direct charge of the work.
General Specifications, Board of Transportation Subway Cars
- Name of Railway. Board of Transportation, City of New York
- Number of units. 300
- Type of unit. Motor, passenger, subway, double end, double truck
- Number of seats. 60
- Builder of car body. American Car & Foundry Co., Berwick, Pa.
- Date of delivery. 1931
- Weight, Car body. 48,300 lb.
- Weight, Motor truck with gears and shoe beams. 14,100 lb.
- Weight, Two motors, less gears. 10,000 lb.
- Weight, Trailer truck, complete. 11,900 lb.
- Weight, Total. 84,300 lb.
- Bolster Centres. 44 ft. 7 in.
- Length over coupler faces. 60 ft. 6 in.
- Length over body posts. 57 ft. 0 in.
- Wheelbase, motor truck. 7 ft. 0 in.
- Wheelbase, trailer truck. 6 ft. 3 in.
- Width over all. 10 ft. 0 in.
- Height, rail to roof. 12 ft. 2 in.
- Door spacing. 14 ft. 11 in.
- Body. All steel
- Air brakes. Westinghouse Traction Brake Co.
- Armature bearings. Bronze
- Anticlimbers. Waugh Equipment Co.
- Axles. Heat-treated carbon steel
- Car signal system. National Pneumatic Co.
- Compressors. Westinghouse D-3-F
- Conduit light-weight steel. Steel & Tubes, Inc.
- Conduit fittings. Appleton Electric Co.
- Control. Westinghouse ABF, UP Type
- Couplers. Westinghouse Traction Brake Co., H-2-A
- Destination signs. Hunter
- Door mechanism. National Pneumatic Co
- Doors. Double, sliding, Four on each side of car, made of aluminum
- Draft gear. Waugh Equipment Co.
- Energy saving device. Coasting clock
- Fans. Westinghouse Elec. & Mfg. Co.
- Finish, paint. 100 cars each Murphy, Dupont and Sherwin-Williams
- Floor covering. Tuco
- Floor sheets. Johns-Manville Co. truss plate
- Gears and pinions. Westinghouse-Nuttall
- Glass. 3/4-in. and 9/10-in. plate
- Hand straps. Waugh Equipment Co.
- Heat insulating material. Johns-Manville Co., Salamander
- Heaters. Consolidated Car Heating Co.
- Headlining in upper deck. Agasote
- Journal bearings. Bronze, 5x9
- Journal boxes. Symington
- Lamp fixtures. Adams & Westlake Co.
- Motors. Two Westinghouse No. 570-D-5, inside hung
- Motor leads, shoe leads and truck trolleys. Okocord and Rockbestos.
- Painting scheme. Dark green
- Roof type. Monitor
- Roof material. Steel
- Sash. O. M. Edwards Co. brass
- Seats. Hale & Kilburn stationary
- Seating material. Rattan
- Signal system. National Pneumatic Co.
- Slack adjusters. Sauvage
- Springs. Chrome-vanadium elliptic and high silicon coils, Pittsburgh Spring & Steel Co.
- Stanchions. Ellcon Co., porcelain enameled
- Switchboards. Consolidated Car Heating Co.
- Trucks. American Car & Foundry Co.
- Ventilators. Monitor sash
- Wainscoting. Thermasote
- Wheels, type. Carnegie rolled steel, diameter 34-1/2 in. motor and 31-1/2 in. trailer
- Wire and cable. Standard Underground Cable Co.
Electric Railway Journal · Vol. 75, No. 5 · May 1931 · pp 282.
300 Cars To Be Ordered for New York Subway
Before the end of the summer the Board of Transportation will place a contract for 300 more steel cars for use on the new subway lines, John H. Delaney, chairman, announced. The new cars will augment the 300 already delivered. Their cost is expected to be about $9,000,000, the price paid for the first 300. Mr. Delaney estimated that about 2,000 cars would be required for the new city lines mapped out in the Board of Transportation's first stage of new rapid transit construction.
Of the first 300 cars, nearly all have been tested in trial runs in the 207th Street yards. Two trains of ten cars each will be tested soon in service conditions on sections of the B.M.T. system to check the efficiency of the four-door construction in loading and discharging passengers.
The car body is divided by the seats into four equal sections, each served by a pair of doors on either side.
[Left] Seats for 60 passengers are so placed that it is easy to reach the nearest doors. [Center] Control equipment is grouped in a permanent cab at each end of the car. [Right] Interior signs show route and destination in clear characters.
A clear passageway through the entire train can be obtained without danger to the passengers. Illuminated route signs are an innovation.
Careful arrangement of the control and auxiliary equipment under the car was necessary to make it readily accessible.
[Top] Each car has one trailer truck of the type shown. All wheels have clasp brakes. [Bottom] The motor truck, while light, is of exceptionally rugged construction. Connections between cars, including air and electric circuits, are made automatically through Westinghouse couplers.