This story has been updated.
PHILADELPHIA -- A conductor on the Amtrak Train that derailed near Philadelphia, resulting in eight fatalities, told investigators she heard radio transmission from the engineer saying his locomotive was struck by something just before it went off the tracks, National Transportation Safety Board officials said Friday.
There is a crack in the train's windshield that could have possibly been caused by a projectile, according to reports.
Two earlier trains that passed through the same line in Philadelphia were reportedly hit by projectiles, according to NBC Philadelphia.
The FBI has joined the investigation and will examine the train.
The 32-year-old engineer Brandon Bostian, who survived Tuesday’s derailment with a concussion and a few other injuries, was interviewed for an hour and a half Friday, in a session in which he was accompanied by lawyers. He was described as being "extremely cooperative," according to NTSA member Robert Sumwalt said.
The engineer does not remember anything beyond passing the North Philadelphia station, Sumwalt said.
The conductor was one of two assistant conductors also interviewed Friday by the NTSB.
For the names and information about those killed in the crash, click here.
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