PHILADELPHIA — The Amtrak train that derailed Tuesday, killing eight people and injuring more than 200, may have been struck by an object before it careened off the tracks, an assistant conductor on the train told investigators from the National Transportation Safety Board.
At a news conference on Friday, Robert L. Sumwalt, the safety board official who is leading the investigation, said an assistant conductor had reported that she believed she heard a radio transmission in which an engineer on a regional line said his train had been struck by a projectile and the engineer on the Amtrak train replied that his had been struck, too.
Mr. Sumwalt said that investigators had found a fist-size circular area of impact on the left side of the Amtrak train’s windshield and that they had asked the Federal Bureau of Investigation to analyze it. He said that the F.B.I. had been called in because it has the forensics expertise needed for the investigation, but that it had not yet begun its analysis.
He said that investigators had also interviewed the engineer and found him “extremely cooperative,” and that the engineer had said he was not fatigued or ill at the time of the accident. But he could not remember anything about the derailment.
Investigators asked the engineer, Brandon Bostian, whether he recalled any projectiles, and he said he did not.
“He was specifically asked that question, and he did not recall anything of that sort,” Mr. Sumwalt said. “But then again, he reported that he does not have any recollection of anything past North Philadelphia.”
The assistant conductor, however, who was working in the cafe car, heard Mr. Bostian talking to an engineer on the Septa regional rail line who said his train had been “hit by a rock or shot at,” according to Mr. Sumwalt. She said she thought she heard Mr. Bostian reply that his train had also been struck.
“Right after she recalled hearing this conversation between her engineer and the Septa engineer, she said she felt a rumbling, and her train leaned over and her car went over on its side,” Mr. Sumwalt said.
Jerri Williams, a spokeswoman at Septa, confirmed that the windshield of one of its trains had been shattered by a projectile near the North Philadelphia station about 9:10 p.m. on Tuesday, about 12 minutes before the Amtrak train derailed.
“We have reports of trains’ being struck by objects in this area about two to three times a month,” Ms. Williams said. Mostly, she said, the objects are thrown by children and do no damage.
The safety board has asked to interview the engineer of the Septa train that was hit by the projectile, and Septa is cooperating, Ms. Williams said.
For days, speculation about the cause of the accident has centered on Mr. Bostian. Investigators reported earlier this week that the train accelerated suddenly a minute before the derailment and that Mr. Bostian applied the emergency brake seconds before the cars careened off the tracks, striking nearby utility poles.
On Friday, Mr. Sumwalt said that the engineer, accompanied by his lawyer, had been open with investigators and had demonstrated a “very good working knowledge” of the proper procedures and speeds for the rail line, but that he did not remember the accident.
“He recalls ringing the train bell as he went through North Philadelphia Station, as required,” Mr. Sumwalt said. “He has no recollection of anything past that.”
Investigators said that Mr. Bostian had been “extremely” cooperative during his interview and that he had “reported no problems with his train handling.”
Read more: NY Times