A badly damaged Amtrak engine was put back on the tracks yesterday as investigators tried to reconstruct a freak train and car collision Saturday night that killed a motorist and injured eight other people.

Prince George's County police still have not determined the identity of the middle-aged man whose car was struck by an eight-car passenger train hurtling toward Washington at an estimated 60 mph.

The man's 1970 Mercury sailed off Kenilworth Avenue at the interchange with Rte. 50 at about 9:10 p.m. on Saturday night and fell about 60 feet, coming to rest on train tracks below, police reported.

Shortly afterward, it was struck by the "Minute Man," an Amtrak train that had originated in Boston. The collision totally demolished the automobile and heavily damaged the train as well.

The front wheels of the engine derailed, the train continued on for another half mile, tearing up about 600 concrete ties on the way. It finally came to rest when the engine struck an abutment at a bridge crossing the Anacostia River.

Among the injured, county police said, were Alton Graham, the train's engineer, of 4300 Kaywood Dr., Mount Rainier; Michael Patterson of 2101 16th St. NW and Helen Crook of 5713 Eliot Ct., Alexandria.

The other injured were identified as James Cherico of Wilmington, Del.; Henry Chinn of Boston; Jo Ann Jackson and Alicia Sample, both of Baltimore; and Henrell Young of Massachusetts.