TSURU, Japan — As the world’s fastest train raced through central Japan, former Gov. George E. Pataki of New York hoisted his 6-foot-5 frame into the aisle and marveled at the smoothness of the ride.

“In the subway I’d need a strap, at least,” Mr. Pataki said as the speedometer hit 315 miles an hour. He hunched over to catch a fleeting glimpse of Mount Fuji through the portholelike windows. “This is amazing. The future.”

The future for Japan, perhaps. For the United States, the future is less clear. Mr. Pataki and other former American politicians were in Japan Saturday for a special test ride of the train, which uses a technology called magnetic levitation, or maglev. They are trying to bring a maglev train to the crowded Northeast Corridor that will cruise between New York and Washington at more than twice the 150-mile-an-hour top speed of Amtrak’s Acela, the fastest train in the United States.

Maglev trains could make the journey in an hour, compared with just under three hours, on a good day, for Acela. That would be considerably faster than flying, especially when getting to and from the airport is factored in. Yet this is only the latest in a series of high-speed train proposals for the Northeast Corridor, none of which has been undertaken since Acela, which began service in 2000.