Flying Trains (Science For Everyone) by G. Zelkin

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These requirements may be viewed as the criteria by which a design alternative can be assessed as being able to perform a given task. What are these criteria? When assessing the capabilities of a vehicle we are above all interested in its speed. A vehicle’s speed depends on many factors, such as the resistance to motion, the power developed by its engine, and the structural design of the vehicle. A very important criterion is also that of economy, which grows in significance and is often a decisive one with the evolution of science and engineering.

Thus, when the train speed rises up to a certain level, as determined by the growing drag, the operating economy of the train in fact improves. At speeds exceeding 400 km h_* the air cushion can be created without fans, simply by the dynamic head of the oncoming air ducted between the bearing surfaces of the train chassis and the track, producing the so-called ram—wing or screen effect. This effect further improves the train’s economy at high speeds. A winged air cushion train (TACV) will not be like ordinary trains in design or appearance.

This design solves two problems straightaway: (i) the shallow water capability of the craft is improved because now it moves above the water, so shallows are not an obstacle; (ii) the hydraulic drag also drops, especially at high speeds, since the hull is not submerged in water. These vehicles may be propelled by a tractor- or pusher— propeller, jet engine, water jet ejected by a pump, or a submerged marine screw. An air cushion for ships was first suggested by E. Svedenberg, a Swedish scientist, in 1716.