The federal government, in what it acknowledged was an effort to allay public fears in the wake of a rash of Amtrak train accidents that killed 13 people this summer, took the media for a ride yesterday on one of its computerized "rail geometry" inspection cars.

Over the next four months, the three specially designed cars equipped with sensors that record roadbed and track imperfections will ride the 24,000 miles on which Amtrak trains travel. One car departed westward from Washington yesterday for Cincinnati by way of Clifton Forge, Va., while two others headed north.

While the cars have been in use for years, supplementing twice-weekly visual inspections, federal officials are touting their mission now as the first systematic inspection of Amtrak nationwide.

Human error and grade crossings cause most train accidents, Federal Railroad Administrator John H. Riley said yesterday during the demonstration ride from Washington to Baltimore.

Nonetheless, he said, U.S. Department of Transportation Secretary Elizabeth Dole ordered the special inspection with its media kickoff "to give the public reassurance that we have left no stone unturned" in making the rails safe to ride.

The only public relations pitfall in the demonstration trip, Riley said, is what may appear to be a greater focus on track problems, although "we really believe the [track] system is strong." However, he said, "after three [fatal] accidents [on Amtrak this summer, only one of them apparently track-related], we have an obligation to do a complete, thorough check of the system."

So, about a dozen reporters and photographers, plus half a dozen Federal Railroad Administration and Amtrak officials boarded the northbound cars at Washington's Union Station for the 37-minute morning ride to Baltimore. The train then proceeded to pick up other reporters in Wilmington, Philadelphia and New York. The train was scheduled to arrive in Springfield, Mass., where the real work was to begin, at 11:30 p.m.

At the center of the "rail geometry" car sat Greg Twitchell, a data specialist with Ensco Inc., which operates the car under contract to the government. Twitchell, 28, monitored a console and printout known as a "strip chart" that revealed any deviation along the track. There was none to speak of.

"Even the novice can tell that's a beautiful railroad," said Russ Baker, an FRA safety official seated in the rear observation area, where a duplicate printout spewed forth from another console. "You just look at the line, the curvature of the railroad."

The train stopped only once, briefly, between Washington and Baltimore, when something dragging underneath it apparently triggered an electronic alarm built into the track. The train crew walked the track and found nothing.

Riley, meanwhile, held forth in the center of the car. He said a dozen railroads now use the rail geometry cars to check their tracks. "This machine notes deviations as small as one-tenth of an inch," he said. Such minute imperfections would be unlikely to cause an accident, he said, "but this may be a check to avoid problems in advance."

According to Joe Walsh, associate federal railroad administrator for safety, 550 of 700 train accidents last year occurred at grade crossings.