The Acela, introduced by Amtrak in 2000, was America’s first successful high-speed train, and most days its cars are full. The train has reduced the time it takes to travel between Washington, New York and Boston, but aging tracks and bridges — including Baltimore’s 100-year-old tunnel where trains come to a crawl — have slowed it down. It takes two hours and 45 minutes to travel from New York to Washington on the Acela. If the Acela were a bullet train traveling on new tracks, it would take 90 minutes.

Another problem is that Amtrak’s funding is tied to annual appropriations from Congress, leaving it without a long-term source of money. “I do what I can do,” said Joseph Boardman, Amtrak’s president. “But I don’t sit back and wait for $15 billion to rebuild the Northeast Corridor.” For now, Amtrak is rebuilding a stretch of track in central New Jersey that will permit travel at 160 m.p.h. for 23 miles.

Image Amtrak’s Acela in Baltimore, where a tunnel slows trains. Credit... Luke Sharrett for The New York Times

But advocates say they are hopeful.

“Once something gets built, then we’re going to see more projects get going,” said Ray LaHood, Mr. Obama’s first transportation secretary. Mr. LaHood said it took the Interstate System of highways decades to be completed, and he predicts that high-speed rail will be the same.

Mr. LaHood said California seemed the most likely candidate for success with high-speed rail, even though plans for a 520-mile train route between Los Angeles and San Francisco have been mired in controversy.

Despite strong backing from Gov. Jerry Brown, a court ruling had tied up state bond funding for the $68 billion project. An appeals court on July 31 threw out that ruling, which had been based on a lawsuit. But opponents are still increasing calls to kill the project, and polls show waning public support for it.

Still, California has begun construction of the tracks and put out bids for a vendor to build the trains. And the new rail project will get an infusion of funds from the state’s cap-and-trade program, which requires business to pay for excess pollution.