The Amtrak switch operator who disappeared for several days after a Pennsylvania derailment that injured 24 people faces an administrative trial on charges he violated railroad operating rules, officials said. Thomas A. Connor, 30, of Aldan, Pa., is also under investigation by the Delaware County district attorney's office, which has been asked by Amtrak to see if any state laws were violated. Connor disappeared shortly after the northbound Amtrak Night Owl went onto a track under repair and hit track equipment 15 miles south of Philadelphia last Friday. Connor surfaced Monday and told investigators he had mistakenly switched the passenger train onto the wrong track because he was distracted. Amtrak officials said Connor could be fired or suspended, depending on the outcome of the hearing.