One person was killed and at least nine others injured last night in a bizarre incident in which an automobile plunged off an overpass in Prince George's County near the District line, fell onto railroad tracks and was struck by an oncoming Amtrak passenger train.

The car was struck by Amtrack's Minute Man, which was passing under the Kenilworth Avenue overpass on its way from Boston and New York to Washington's Union Station. The impact derailed the Minute Man's engine.

According to preliminary reports, the driver of the car was killed, and investigators said they would seek to determine whether his death was caused by the plunge from the overpass or the impact of the train.

tFirst accounts of the unusual incident indicated that the car may have been struck on the bridge by another vehicle.

One of those injured was the engineer of the train, who suffered a broken leg. He and another person who suffered fractures were taken to Prince George's General Hospital. They were being examined in the emergency room early this morning.

Most of the passengers and crew members of the southbound train, were brought by a following train, the Florida-bound Sliver Meteor, to the Amtrak passenger facility at Union Station here.

After evaluation, seven were taken from the station to hospitals in the District of Columbia, with injuries described as mainly bumps and bruises. Five of the seven were passengers and the other two were crew members.

An Amtrak spokesman, who noted that Saturday evening rail ridership is traditionally light, estimated that the non-reserved-seat train, which makes several stops between New York and Washington, was carrying 34 passengers in its eight cars when the crash occured about 9 p.m.

The Amtrak spokesman said the train had just stopped a few miles to the northeast, at the Capital Beltway Sataion, and expressed doubt that it had accelerated to more than 50 or 60 miles an hour at the time of the collision.