On a desolate stretch of track just before midnight, when all passenger lines have been put to bed, a juiced-up Japanese bullet train goes online and accelerates to more than 200 miles per hour. The 700-ton train, about a quarter of a mile long, whooshes by rice paddies in seconds.

There are no locals around to witness the train glide to a stop at a deserted Kyoto Station, but that’s not the point. This is an accelerated sales pitch aimed squarely at the United States, where Japan is competing with European train makers for a new highspeed train network that could deliver contracts worth hundreds of billions.

Diplomats, business leaders and journalists were crammed in to watch special speedometers ...