Amtrak canceled several runs of its high-speed Acela trains yesterday after inspectors found indications of substandard maintenance practices, officials of the passenger railroad corporation said.

Amtrak canceled nine of 44 scheduled runs between Boston, New York and Washington, and used other equipment to fill in on four other passenger runs. That included three early-morning cancellations from Washington's Union Station and substitution of other equipment on one trip.

Company spokesman William Schulz said enough trains will be available to cover weekend schedules, but beginning Monday, only 36 of the 44 regular weekday East Coast departures will operate. In Washington, that means the 5 a.m. and 6 p.m. Acela departures will be canceled; the noon Acela will be replaced with Metroliner service; and the 5:30 Metroliner will be canceled. Schulz said it is not yet clear how long the reduced schedule will remain in effect. Amtrak's regional trains, which cover the same East Coast routes as the Acela and are more numerous, will not be affected.

The cancellations are another setback in the relationship between Amtrak and the makers of the 150-mph trains, Bombardier of Montreal and Alstom of Paris. The Bombardier-Alstom consortium formed a management group, the Northeast Corridor Management Service Consortium, to handle maintenance of the trains. The group uses Amtrak union employees, but managers are from the consortium.

The current problems with the 304-passenger trains have nothing to do with cracks discovered last year in yaw-damper brackets on the locomotives. At that time, all Acela trains were removed for repairs.

William L. Crosbie, Amtrak's senior vice president of operations, said the problems found over the past week are not safety related, but involve maintenance that is not in compliance with recommended practice. Most of the problems involve leaking shock absorbers on passenger cars and grooves worn in disc brakes, he said.

The core problem, Crosbie said, is that the Bombardier-Alstom team hasn't kept up an orderly flow of spare parts to maintenance centers in Boston, New York and Washington.

"We certainly aren't happy," Crosbie said, adding that Amtrak is working with the consortium to fix the problems.

David Slack, a spokesman for Bombardier, acknowledged that some problems had been found during the week, but said, "We think we're doing the best job we can." He said the consortium is providing quality maintenance and is working with Amtrak to smooth out the spare-parts issue.

Amtrak and the consortium are suing each other over damages for late delivery of the trains and other quality issues.

In routine inspections last weekend, the Federal Railroad Administration noted the maintenance problems and recommended they be fixed, but did not directly order the trains out of service. However, on Tuesday, Amtrak itself took three trains out of service for repairs. Yesterday, four others were removed.