A little yellow hangar stands on reclaimed land beside Tokyo Bay, desolate as the Wright brothers' primitive airfield in North Carolina.

he wind rattles in tin roof, and the mechanics wear goggles against clouds of flying sand as they roll out their hand-built experimental vehicle.

Moments later, electromagnetic force takes over, effortlessly hoisting the one-ton fuselage into the air and propelling it down a track at 40 miles an hour. The effect is eerie: There is no sound except for a faint high-tension hum and the flap of a Rising Sun flag on the streamline nose.

It is one of three "flying trains" under development in Japan and is officially called the High Speed Surface Transport. While the famed "bullet train" system carrying a half-million passengers daily at speeds up to 130 miles per hour is still the world's fastest, engineers are planning replacements. The technology exists, they say, for a 500-ton train to move four inches above a magnetic track at 300 miles an hour.

On the "flying trains" passengers will be able to drink sake and snack in comfort. "The ride should be as smooth as an airplane, withcut air-pocket," said Yoshihiro Kyotani, head of a Japanese National Railways research team.

The "flying trains" will cut travel times by two-thirds and in concept sound like an environmentalist's dream. They promise no polluting exhaust emissions and sharp reductions in the noise and vibration levels that make life miserable for people living along the bullet train tracks.

Other countries are developing similar high-speed rail transport, including the United States, Canada, West Germany, the Soviet Union, Britain and France The Japanese, who believes they are ahead, want to be the first to bring the "flying trains" into regular service.

Closest to reality of the three is the high/speed/surface train, an airport to-city system developed over the last 13 years by a team of Japan Air Lines engineers.

If funds and government approval come through as hoped, the train could be speeding passengers from Haneda Airport to Tokyo at 190 miles an hour by 1980. A trip that can take an hour in Tokyo traffic would shrink to four minutes.

The airline would like to build a 50-mile track to link Tokyo with Haneda and the new international airport at Narita.

Built four years ago, the Narita airport is still unopened, partly because local organizations have blocked constructions of a rapid-transit link with Tokyo. If the airport were open, it would take travelers two hours to cover the 40 miles to Tokyo. The high-speed train could do it in 14 minutes.

Japan's national airline went into the rail business because traffic between cities and airports has cut the time advantages of air travel. "By improving the city-to-airport surface transport we can give the passenger back the main advantage of air travel - speed," said Japan Air Lines Director Hideo Hirasawa.

The high speed surface transport is raised by electromagnets and accelerates rapidly as linear induction motors react to a central track of aluminum-coated iron. Rockets are expected to bring the experimental vehicle up to 190 miles an hour on a one-mile test track in trials this summer.

The high speed train would operate on one-third the electricity of a conventional train. Construction costs are staggeringly high and the airline is looking for government and private investment. A 40-mile track between Tokyo and Narita would cost $1 billion.

Further off is the national railways 300-mile-an-hour train, which is to undergo trials for seven years at an experimental center in Kyushu. The ultra-high-speed train is the railways' major research project. A 43-mile test track costing $44-million is being built in sparsely populated farmland.

Technical Development Director Kyotani, 51, has worked on the train since 1970. "Time is precious and fast is good," he said."We think this is the transportation mechanism of the next generation, and we know it's going to happen."

The argument for the ultra-high-speed train is the near-saturation of the bullet train service between Tokyo and Japan's second-largest city Osaka.

The trains run at 100 miles an hour as often as every five minutes. Experts say passenger capacity will be reached by 1980. The new railways' train, which would cover the 343 miles in about an hour instead of the three-and-a-half hours required by the bullet train may be the answer.

The third train of the future designed to float on a magnetic cushion is an urban and commuter system. It is being developed for the Japanese Transport Ministry by three major electric machinery manufacturers and works similarly to the high speed surface train.