Engineering Wonders of the World
Volume I

350 ENGINEERING WONDERS OF THE WORLD. two and a half mile intervals. The former ar© merely recessed outward from tho side walls of the Subway. The „ The express stations have “ island Stations. platforms between the tracks. One of them is shown by the view Fig. 12. The platforms are up to 350 feet long, and are at the level of the car floor. Concrete, steel, and ornamental and glazed tile (to reflect Fig. 11.—SUPPORTING A COLUMN OF THE ELE- VATED RAILWAY WHILE THE SUBWAY EXCAVA- TION WENT ON UNDERNEATH. The original base of the column is seen under the girders on which the temporary brackets rest. {Photo, Pierre P. Pullis.) Fig. 12.—A TYPICAL EXPRESS STATION AS IT AP- PEARED BEFORE TRAFFIC COMMENCED. The two “express” tracks are between, the “local” tracks outside, the two platforms. Fig. 13.—CONSTRUCTING A WIDE-SPAN BRICK ARCH AT 168th street station. Tunnel in rock, 150 feet below the surface. {Photo, Pierre P. Pullis.) a maximum of light) are the only materials that enter into the station construction. Glass vault-lights in the street sidewalks above and large numbers of incandescent lamps light the stations. And now just a few words on the equipment of the Subway—that is, the signals, power system, and cars. Without stopping to notice the track work, with its ballast-bedded cross- j . .. Signals. ties and its third rail carry- ing the power current, we must glance at Fig. 14.—A STRETCH OF THE ELEVATED PORTION OF THE SUBWAY WITH STATION, NEAR NORTH- ERN TIP OF MANHATTAN ISLAND. the block signal equipment, a very essential safety provision. The express trains make long high-speed runs, at speeds up to 45 miles per hour. Darkness and curves render it impossible to