The New York Rapid-transit Subway

24 PARSONS ON NEW YORK RAPID-TRANSIT SUBWAY. [Minutes of weight of 100,000 lbs. on four axles, giving a load of 12,500 lbs. per wheel, with unit stresses in the longitudinal girder-flanges of 10,000 lbs. per square inch. The permissible stresses in the flanges of the cross girders varied with the number of tracks, being 10,000 lbs. when one track was carried, 12,000 lbs. for two, and 13,000 lbs. for three. Stations. The stations are of three distinct types :— A. “ Local” stations on four-track sections with the platforms outside the outer tracks, at which only local trains stop. B. " Express ” stations on the four-track section at winch both express and local trains stop, witli island platforms between each pair of local and express tracks and sometimes additional platforms on the outside of the local tracks, permitting the passengers on the local trains to embark from and disembark to platforms on both sides. C. Stations on the two- and three-track sections at whicli both local and express trains can stop. The stations of this third type have platforms exterior to the outer tracks, except two on the two- track sections which have each a single island platform. The number of stations of the several types are:— Type A........................17 „B........................... 4 » c .........................37 The basis of the design for all stations was to have all the plat- forms as close to the surface of the street as possible, so as to give the minimum height of staircase from platform to side-walk and avoid the use of mechanical means of ascent and descent. The minimum distance from the rail-level to the surface of the street being 17 feet, and the platform-level being arranged to be 4 feet above the base of the rails, the minimum distance from platform to street-surface was about 13 feet, which has been approximately realized at nearly all the underground stations. Stations of type B were necessarily depressed in order that access might be had to the island platforms, as will be explained later. What may be called a standard station of type A is in plan like the letter T with arms elongated parallel to the track, while the stem is under the street transverse to the main route. Beneath the cross street is located tlie station with the ticket-offices, lavatories,