WASHINGTON (AP) _ Amtrak's cost-saving policies have undermined public safety, rail workers told Congress today, but the railroad called the complaints a smokescreen for a simple wage dispute.

The allegations by Amtrak union officials and employees based in Boston are the latest salvo in a running labor dispute between the railroad and its workers in the Northeast Corridor. They also come in the midst of investigations into two recent collisions involving Amtrak trains in the corridor.

Most of Amtrak's workers have gone three years without a wage increase. So strained are labor-management relations at Amtrak in Boston that members of the Massachusetts congressional delegation intervened and sought a review by the House Government Operations transportation subcommittee, which called today's hearing.

Workers contended that efforts by Amtrak to make a profit and eliminate the need for government subsidies by the year 2000 have led to reduced maintenance and training.

They said Amtrak has reduced inspections of its cars, including the brakes; cut back on signal maintenance, allowed engineers to operate trains without adequate training and retaliated against employees who spoke out.

''I can cite to you specific instances of trains being ordered to depart Boston with defective brakes over the objections of the on-duty car inspector and the train crew, instances of doors flying open at high speed for no apparent reason,'' Harold G. Malone, legislative director of the United Transportation Union, said in prepared testimony.

Amtrak employee Albert January said in prepared testimony that testing of Amtrak's signal apparatus between Providence, R.I., and Boston was ''grossly overdue'' in late 1990 in the weeks before a major accident at Boston's Back Bay Station.

And another employee, Paul Hanson, alleged that car inspectors who test train brakes, ''had little or no training. ... I, myself, observed brake valves left in a cut-out position, brake shoes worn too thin, and air leaks not reported.''

''There are serious charges that need to be looked into,'' said subcommittee Chairwoman Barbara Boxer, D-Calif. ''The atmosphere at the Boston-area Amtrak is nothing short of poisoned and we need to find out why.''

Amtrak Executive Vice President Dennis F. Sullivan said in prepared testimony that the railroad has never sacrificed safety for the sake of operating free of federal subsidies.

''It would be irresponsible for any Amtrak employee to alarm the public by attempting to recast non-safety related issues - such as compensation or work location - into public safety concerns,'' Sullivan said. ''Safety is too important an issue to be used as leverage in labor disputes and negotiations.''

The hearing comes as federal investigators probe the Dec. 12, 1990 crash at Back Bay Station that left 267 injured and the April 12 collision of four Amtrak locomotives with a Conrail freight train in Chase, Md., that injured two employees.

In the Boston crash, a speeding Amtrak train derailed and slammed into the rear of a packed commuter train. The investigation revolves around whether the engineer and engineer-trainee were negligent in speeding into the station or whether they were victims of equipment failure and a ''death trap'' speed zone.

Amtrak employees and union leaders acknowledged that issues of salary and work rules are a primary concern.

Much of the testimony of 19-year Amtrak employee Charlie Moneypenny, for example, focused on worker-management disputes over such things as on-the-job injuries, drug testing and staffing levels.

An officer of the unions' Railway Labor Executives Association raised the possibility of a strike if wage and other issues continue unresolved. ''None of us relishes the idea of a strike on Amtrak,'' said association Treasurer James J. Kennedy. But, he added, ''we are approaching the end of the line.''

Sullivan said employees have been offered a 3 percent raise with retroactive pay to cover the past three years. The problem, he said, is that Amtrak's labor negotiators want to see the terms of a pending agreement between railroads and freight workers who recently went on strike.