WASHINGTON - Amtrak's planned new Acela Express trains will carry more passengers and be more reliable than the current ones, even if they won't travel much faster, Amtrak president Joseph Boardman said Thursday.

Amtrak is seeking proposals, with the California High-Speed Rail Authority, for new high-speed trains that can run at 220 miles an hour on the West Coast and 160 miles an hour on the Northeast Corridor.

Proposals from train-builders are due by May 17. A builder will be selected by the end of the year, Boardman said.

The first of the new Acela trains are supposed to be in service between Washington and Boston by 2018.

The specifications for the new trains call for many different requirements for Amtrak and for California, but Boardman said he was optimistic that train manufacturers could come up with a common design that could be modified to fit both.

If not, he said, Amtrak will proceed on its own to purchase new Acelas, expected to cost about $50 million each.

"We're going to get a train set that operates for us. We hope it's useful to California . . . but California is not my problem," Boardman said in an interview.

Amtrak in 2012 outlined a $151 billion vision for high-speed travel on a rebuilt Northeast Corridor, with 220-m.p.h. trains between New York and Washington by about 2030 and between New York and Boston by 2040. That plan envisioned 37-minute trips between Philadelphia and New York.

That is still Amtrak's long-range goal, Boardman said, but that vision must be balanced against today's reality: The Northeast Corridor, with its current configuration and equipment, can't handle trains faster than 160 miles an hour.

Amtrak's Acela Express trains now travel up to 150 miles per hour on a short stretch in New England, but the top speed between New York and Washington is 135 miles an hour.

And the train's average speed is considerably lower: On the 319-mile trip between Philadelphia and Boston, including stops, Acela averages about 64 miles per hour.

Amtrak is currently rebuilding a 23-mile stretch of track in central New Jersey that will permit 160-mile-an-hour travel. Boardman says that $450 million project is part of a gradual approach to upgrading the corridor, with limited money from Congress and no multiyear funding.

"We do it a piece at a time. I do what I can do," Boardman said, "but I don't sit back and wait for $15 billion to rebuild the Northeast Corridor."

In the railroad's current budget request, Amtrak is seeking authority to use the operating profit generated on the Northeast Corridor to upgrade the corridor. Currently, that profit is used to help subsidize money-losing, long-distance operations elsewhere in the country, Amtrak says.

The new Acela trains are to carry about 450 passengers, compared with the current capacity of 304. That will help increase capacity on the crowded Northeast Corridor, Boardman said.

Amtrak envisions buying 28 new train sets to add to its current fleet and to replace the 20 existing Acela train sets in the early 2020s.

The new state-of-the-art trains will be more reliable than their predecessors, improving on-time performance, he said.

But the specifications for the new trains do not call for much improvement in current travel times.

The new high-speed trains will be required to make the trip between New York and Washington in no more than 2 hours and 45 minutes, which is the same as some currently scheduled Acelas. The specified travel time between Boston and New York for the new Acelas is 3 hours and 30 minutes, seven minutes faster than current schedules.

Boardman on Thursday renewed his call for Congress to approve a new way of funding Amtrak, instead of relying on annual appropriations. The railroad needs the certainty of multiyear funding to make long-term improvements, like new tunnels into New York City and Baltimore, new bridges, and improved signals and power equipment.

"What the hell is wrong with this country?" Boardman said. "We're eating our assets alive.

"The debt to the future has to be paid by us," he said. "What we need to do now is to provide for the next 100 years."