SEPTA police and authorities in Bucks County are investigating a deadly accident on the rails.MORRISVILLE, Pa. (WPVI) -- SEPTA police and authorities in Bucks County are investigating a deadly accident on the rails.A Trenton Line Regional Rail train struck a person in Morrisville, just north of the Levittown station. It happened at 7:30 p.m. Thursday.It is unknown what the victim had been doing on the tracks.