300 mph trains yet to prove reliability

October 25, 1992|By Douglas Birch | Douglas Birch,Staff Writer

Trains that float on a cushion of magnetism at more than 300 mph may seem like a notion lifted from some hokey science fiction novel.

But magnetic levitation trains have operated on test tracks for more than a decade in Germany and Japan. And an international group, using German technology, plans to start building the world's first high-speed passenger line in Florida next year.

The real challenge, a National Research Council report warned last year, is to demonstrate that "maglev" can handle the perils and punishment of serving the traveling public.

"It remains to be proven that they can achieve reliability in operation," said Dr. Tony Eastham, an electrical engineering professor at Queen's University in Ontario, Canada, who helped write the report.

All maglev systems work on the same simple principle. Magnets, of course, have a north pole on one end and a south pole on the other. This is called polarity. And, as we discovered as children, if you take the north pole of one magnet and hold it near the south pole of another one, the two magnets are pulled together by an invisible force. If you put the north poles together, the two magnets repel one another.

Both maglev vehicles and their guideways are equipped with powerful electromagnets, some of which repel each other, causing the vehicle to float.

Electromagnets also propel the vehicles. Computers quickly switch the polarity of an array of magnets in the track to constantly pull the vehicle from ahead and push it from behind.

Maglev vehicles weigh many tons, and it takes enormous energy to float them even short distances. So they can levitate only a few inches from their guideways. This means guideways must be built to exacting specifications and would likely require far more maintenance than do railroad tracks or superhighways.

A magnetic levitation train must also be equipped with highly sensitive and reliable electronic sensors to constantly monitor acceleration as well as the vehicle's up-and-down and side-to-side motions. The sensors alert computers to make split-second adjustments to speed up or slow the train and to keep it from bouncing or slamming around.

Next year, a consortium of German, Japanese and American firms expects to begin building a $622 million, 14-mile line between Orlando International Airport and the hotels along International Drive near Disney World. At 250 mph, the trip would take only 5 1/2 minutes. Set for completion in 1997, the line is to carry up to 400 passengers in each four-car train. The U.S. government has provided $97.5 million. The consortium has pledged another $90 million and will finance the balance.

"This particular application is a very important one," said Dr. Eastham. "It will demonstrate that that particular form of maglev can be taken from a research environment and put into service."

The Orlando group will use the German maglev system, developed by Transrapid International, a joint effort of the German government and several German firms that since 1980 have operated a 19-mile, figure-eight test guideway in Emsland, Germany.

The German system uses conventional electromagnets to pull the vehicle upward to within three-eighths of an inch of iron rails attached to the T-shaped elevated guideway. A separate array of electromagnets on the bottom of the train propel the vehicle forward above the guideway's central steel rail.

The Japanese system, based on technology developed in the United States, uses superconducting wire within the vehicle. The wire produces a magnetic field of the same polarity as coils embedded in the guideway. The repulsive force levitates the train about four to six inches above the guideway, and helps propel it forward.

A 25-mile test guideway is planned for a site near Tokyo, expected to become the first leg of a 310-mph line linking Tokyo and Osaka. But Dr. Eastham said the technology is still about a decade away from serving Japanese commuters.

Four teams of companies in the United States are trying to come up with a design for a maglev system that American firms can build and sell. Construction of a commercial maglev system using U.S. technology is probably 15 years away, experts say.

Maglev proponents defend the safety of their systems. But the technology is not immune to mishaps. Last year, a Japanese maglev vehicle was destroyed by fire during testing.

One concern is that a power failure might slam the train onto its guideway with a jolt, damaging the vehicle or injuring passengers.

Charles H. Smith of the Florida High-Speed Rail Commission said Orlando's maglev line will have back-up generators and batteries to float the train to the nearest point where passengers can get off.

Larry Johnson, director of the Center for Transportation Research at Argonne National Laboratory near Chicago, said the trains are also protected by pairs of runners on the bottom of the vehicles. The runners would act as skids, he said, to help avoid damage to the vehicles if they fell onto the guideway.

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