Experimental rail-bus to beat congestion on expressway
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AN experimental vehicle—a bus which can operate on railway tracks as well as on highways—was shown publicly for the first time in New York last month. Sponsored by the Port of New York Authority and the Metropolitan Commuter Transportation Authority, it is being evaluated as a means of improving travel between the central business districts of cities and their metropolitan airports.
Under the road/rail plan, the combination vehicles would travel from the Manhattan terminal through the Queens Midtown tunnel as buses. They would then lower their rail wheels and operate on MCTA tracks from Long Island City to a point near the airport, thus by-passing the crowded Long Island expressway. The vehicles would then retract the rail wheels and proceed as buses to individual airline terminals at the airport.
The prototype rail-bus was created by installing retractable rail wheels on a standard 4I-passenger General Motors bus, the same model used in several major 'cities to provide airport access service. As can be seen from the drawing the conversion gear consists of four legs rigidly attached to the bus structure.
Each leg contains a hydraulic cylinder to raise and lower the rail wheel units vertically to the on-rail and off-rail positions. An electrically driven hydraulic pump, operating from the electrical system of the bus, supplies the hydraulic system. Each leg also contains a pressurized air chamber to maintain positive wheel contact with the rail and provide suspension for the vehicle.
Two 12+in-diameter flanged steel rail wheels are carried by rocker arms mounted in tandem at the bottom of each leg. For rail operations, the front rail units raise the front wheels of the bus clear of the rails. The entire front axle load is then transferred to the front rail wheels. The inner tyres of the dual rear wheels rest centrally on the rails and the bus rear axle load is shared between the inner tyres and the rear rail units. Simple disc brakes are fitted to each rail wheel, operated from the bus air brake system through the normal brake pedal.