The Flying Railroad

The sleek, bullet-nosed vehicle looks like something off a rocket designer's drawing board. But the shape of the futuristic train is highly functional. As it quickly and quietly gathers speed, it will actually begin to "fly." The streamlined cars will hurtle forward just above the ground at speeds of 300 m.p.h. or more. For the 1,000 passengers on board, the trip will be strikingly smooth and vibrationless.

The Japanese will probably be the first to enjoy so easy a ride. One of the more exciting technological exhibits at Expo 70 is a scale model of just such a train; and the Japanese National Railways hopes to put its new "Super-Super Express" in service for the 310-mile ride between Tokyo and Osaka by 1980. Controlled entirely by computers, it will easily eclipse Japan's Tokaido super express, which, at 130 m.p.h., is now the world's fastest scheduled train.

Idea's Beauty. The secret of the swift, silent ride is simple magnetism. Even before World War I, a farsighted French inventor, Emile Bachelet, demonstrated the feasibility of lifting railroad cars slightly off the track and propelling them forward with strong electromagnetic forces. The beauty of Bachelet's idea was that it virtually eliminated rail friction. But the technology of that day was unable to produce sufficient electricity at a low enough cost.

Modern research has now overcome that obstacle with powerful new electromagnets. Chilled to --450DEG F. by a jacket of liquid helium, their coils become superconductive. As the temperature approaches absolute zero ( -- 459.7DEG F.), internal resistance to electrical currents virtually disappears. Even a slight pulse of electricity will keep currents flowing in the coils for indefinite lengths of time. Except for the electricity needed to refrigerate the helium, strong magnetic fields could thus be created in superconductors with a minimal use of power.

The Japanese are not the only ones working on such a train. In a similar design proposed by Stanford Research Institute at Menlo Park, Calif., the mag-net:c train rides on a concrete pathway about twelve feet wide. Ordinary rails have been replaced by two L-shaped aluminum guide strips (see diagram). As the train's speed increases, the magnets on the underside of the cars act like the moving armatures of an electrical generator, causing currents to flow in the aluminum strips. These currents, in turn, bu:ld magnetic fields of their own. Just as like poles of ordinary horseshoe magnets repel each other, so do the train's superconductive magnets repel their magnetic "mirror images" in the aluminum strips. In this way the train can be lifted as much as a foot off the ground. If the train drifts slightly to one side, as it will on a curve, the repelling magnetic forces on that side of the pathway will become even stronger, thereby edging the train back to its proper position.

Lift-Off. Nicknamed "Maglev" (for magnetic levitation) by the Stanford engineers, the train could use any number of propulsion systems: propellers, jet engines or even rocket motors. But both Japanese and American designers favor linear induction motors. These are similar to conventional electric motors, but they have, in effect, been flattened out. Part of the undercarriage of the train acts as the motor's fixed coils, while a vertical guide rail in the center of the pathway takes the place of its spinning rotor. When enough electrical power is fed into the system, the train begins to move forward. Like an airplane, the train needs old-fashioned wheels for low-speed travel until it reaches "liftoff" at about 50 m.p.h.

The design of the magnetic train has been worked out in considerable detail; the greatest hurdle to actual production is money. One rough estimate is that the Super-Super Express will cost the Japanese at least $3.5 billion. The U.S. Government, for its part, has not made any commitment to such an expensive scheme. But the California researchers are hopeful that they will eventually get funds from Washington. They have already decorated their office walls with a poster that reads, MAGLEV, NOT WAR.

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