1-A SUPPLY TRACK - EE WAS STANDING BESIDE A TRACK CARRIER WHILE CO-WORKER WAS LIFTING TAILPIECE OFF OF IT WITH A UNI-TRAC. AS THE TAILPIECE WAS BEING LIFTED A LOOSE BELT ROLLER WHICH WAS ALSO ON THE CARRIER FELL TO THE PAVEMENT AND STRUCK INJURED A GLANCING BLOW TO HIS RIGHT THIGH.