Investigators uncertain anything hit train before derailment...

Federal authorities said they are uncertain if anything struck the windshield of an Amtrak train before it derailed in Philadelphia last week, but they have not ruled out the possibility

Investigators, however, said they are certain a gunshot did not strike the train before the May 12 derailment, which killed eight people and injured more than 200 others.

FBI agents performed forensic work on a grapefruit-sized fracture on the left side of the Amtrak locomotive's windshield, and the National Transportation Safety Board said they found no evidence of any damage that could have been caused by a firearm.
The developments came Monday as trains began running to New York again for the first time in nearly a week. They also raised new questions about the events leading up to the derailment, including a conversation an assistant conductor told investigators she heard between the Amtrak engineer and a regional rail train engineer minutes before the train sped up and went off the rails at a curve.
The assistant conductor said she heard the regional train engineer say he'd been "hit by a rock or shot at" and she thought she heard the Amtrak engineer say his train had also been struck.
The NTSB said the regional train engineer recalled no such conversation, and investigators listened to the dispatch tape and heard no communications from the Amtrak engineer to the railroad's dispatch center to say that something had struck the train.

The Southeastern Pennsylvania Transportation Authority said it doesn't know what caused the damage to its train that night. click here for more.