Amtrak said yesterday that it has countersued the Canadian-French consortium that built the trouble-plagued Acela trains for its premium Northeast Corridor services, asking for more than $200 million in damages.

The lawsuit comes almost exactly one year after one member of the consortium -- Bombardier Inc. of Montreal -- filed a $200 million suit against Amtrak, charging that the national passenger railroad refused to pay for cost overruns caused by Amtrak's indecision and failure to live up to the contract.

Amtrak's motion to dismiss the Bombardier suit was denied Sept. 30. It is appealing. Amtrak spokesman Cliff Black said yesterday that Amtrak had to countersue by Wednesday -- the day the suit was actually filed -- or lose the right to do so.

The Acelas, capable of running at 150 mph, have suffered numerous mechanical problems that have led to frequent service delays and cancellations since their introduction in December 2000.

The latest problem -- cracking in a bracket assembly on a shock-absorber-type system designed to prevent rocking from side to side at higher speeds -- caused all Acela train sets to be pulled out of service for several days. Fifteen high-horsepower locomotives that were part of the same order also were pulled out of service.

After a temporary fix was devised, most of the train sets were returned to service. Of the 20 train sets originally ordered, 12 are in regular service, three are being held in reserve, four are in the shop for maintenance or repairs, and Amtrak has not accepted one for service. All 15 high-horsepower locomotives are back in service.

New York-Boston Acela service has returned to the full schedule -- nine weekday round trips -- that it operated before the problems were discovered. Between Washington and New York, 12 round trips are now being made, compared with 16 previously, and two Metroliner round trips have been added.

Numerous slower Amtrak trains and hundreds of commuter trains also operate over large portions of the Boston-Washington corridor.

Amtrak's countersuit included no major issues that have not already been aired in public. It said all the train sets were delivered at least a year late, some more than two years late. The suit also said the trains have failed to meet operating-performance targets included in the contract, costing Amtrak millions of dollars in revenue and inconveniencing its customers.

It also contends that Bombardier's original suit broke the contract because the consortium had promised to submit any disputes to arbitration.

Amtrak President David L. Gunn said in a statement that Amtrak will continue to work closely with Bombardier and its partner, Alstom, to solve the Acela's operational problems, but "we must exercise our fiduciary responsibility and seek damages for the extensive delays in delivery and the service problems that are the responsibility of the manufacturer."

Bombardier spokeswoman Carol Sharpe said Bombardier welcomes the Amtrak action because "it's one more step in the resolution of the issue."

Sharpe said the company still thinks its claim is strong, but "we are hopeful we'll come to a settlement" before the suit ever comes to trial. She said some talks between Amtrak and the consortium are continuing. "It's time to get this behind us," she said.

An Acela sits parked at Union Station in July after inspectors found cracks in a bracket assembly on a shock-absorber-type system on the trains.