One of the assistant conductors on the Amtrak train that derailed Tuesday, killing eight people and injuring more than 200, has told investigators that just prior to the crash she heard a radio transmission from the engineer that the locomotive had been struck, the National Transportation Safety Board said Friday.

"Our investigation has not independently confirmed this information, but we have seen damage to the left-hand lower portion of the Amtrak windshield that we have asked the FBI to come in and look at for us," NTSB board member Robert Sumwalt said.

The FBI planned to conduct the examination Friday night.

Sumwalt said the assistant conductor also said she previously heard the engineer of a regional SEPTA train telling the train dispatcher he had either been hit by a rock or shot at. The SEPTA train had a broken windshield and its engineer placed his train into emergency stop, Sumwalt said.

Sumwalt said the engineer on the Washington-to-New York Amtrak train does not remember anything after the train passed the North Philadelphia station. He said investigators interviewed the engineer, Brendan Bastion, 32, and described him as "extremely cooperative."

"He reported no problems with train handling," Sumwalt said, adding the engineer felt no fatigue or illness.

Sumwalt said the agency had also obtained the SEPTA train's outward-facing video and would review it.

As we reported Thursday, the train accelerated to more than 100 mph just before it entered a turn rated for 50 mph; the engineer then slammed on the brakes to slow the train down.

Meanwhile, Amtrak President and CEO Joe Boardman said the company "takes full responsibility and deeply apologizes for our role in this tragic event."

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