President Bush on Wednesday appointed an emergency board to help Amtrak settle its dispute with nine labor unions and avoid a crippling strike during the busy holiday season.

The intervention had been expected, though unions had been making preparations for a strike just in case.

About 10,000 Amtrak workers have been working under outdated contracts for nearly eight years. However, the Railway Labor Act does not allow them to strike until federal officials determine that mediation has been unsuccessful.

The National Mediation Board released the parties from mediation Nov. 1, which triggered a 30-day cooling-off period. If not for Bush's order, the unions would have been free to strike after the cooling-off period expires Friday night.

Under the order, the five-member presidential emergency board will have 30 days to recommend a resolution, starting at 12:01 a.m. Saturday. Amtrak and union officials have said they expect an extension to be granted because of the holidays.

Wednesday's order did not name the members of the board.

After the emergency board completes its work, the law requires another 30-day cooling-off period. At the end of that, if Amtrak or the unions reject the board's recommendations, the workers can strike. However, Congress also can intervene to compel the parties to accept certain terms.

Amtrak has never had a strike in its 36-year history. If one were to occur, it would bring all Amtrak operations to a standstill, since even non-striking unions would honor picket lines, said Amtrak spokesman Cliff Black.

A strike also would cripple some commuter railroads on the northeast corridor, where Amtrak owns the tracks. Chicago's Metra would not be able to operate trains into Union Station, where Amtrak controls access, Black said.

Black said Amtrak was pleased to have at least another 60 days to reach an agreement.

"We are hopeful that we can entirely avoid any disruption of service as a result of this," he said.

John Thomas, chairman of the Brotherhood of Railroad Signalmen Local 18 in Philadelphia, said he was hopeful the emergency board would come up with something fair. He said an emergency board appointed by Bush in a previous dispute involving the Metro-North commuter line in New York came up with an agreement that was good for workers.

"If it's not what we want, then we will definitely go on strike when the cooling off period is over," he said.

The major sticking points in the negotiations have been back pay and proposed work rule changes.

Amtrak has offered raises but refuses to make them retroactive for the years of negotiations. Since the contract's term ended at the end of 1999, workers have received only small, incremental wage increases equal to half the increase in the cost of living.

Amtrak has said it is seeking work rule changes to give it the flexibility to assign employees to different jobs. The unions say this would result in people performing new jobs without proper training, leading to dangerous situations.