US National Transportation Safety Board (NTSB) said on Friday the Amtrak train that derailed in Philadelphia killing eight people and injuring more than 200 may have been struck by an object before the crash.
NTSB member Robert Sumwalt based the claim on the accounts of an interview with the train’s assistant conductors who said she heard a conversation between the train’s engineer and another Southeastern Pennsylvania Transportation Authority (SEPTA) train.
“She recalled that the SEPTA engineer had reported to the train dispatcher that he had either been hit by a rock or shot at, and the SEPTA engineer said that he had a broken windshield, and he placed his train into emergency stop,” Sumwalt said.
“She also believed that she heard her engineer say something about his train being struck by something.”
The derailed train’s engineer Brandon Bostian (32) was also interviewed by NTSB officials but said he had no memory of crash or the moments leading up to it, and he was not sick or tired while on duty.
Sumwalt described Bostian’s behaviour during the interview with the investigators as “extremely cooperative.”
The Federal Bureau of Investigation (FBI) was called in to examine a circular pattern on the remnant from the lower left-hand corner of the locomotive's shattered windshield to determine whether it was caused by an object before the crash.
The new development added a new aspect to the possible cause of the derailment as the investigators were earlier focusing on speeding as the probable reason.
NTSB officials said on Wednesday the train was moving at a speed over 160 kmh just before the derailment on a left turn curve where the speed limit is 80 kmh, and the engineer used emergency brakes just before the crash but could not slow the train down.
NTSB said the rail section on where the train derailed was not equipped with a new safety system called “positive train control” (PTC) that manages the speed of trains and slows them down if they are moving too fast to prevent accidents.
"Based on what we know right now, we feel that had such a system been installed in this section of track, this accident would not have occurred," Sumwalt said on Wednesday.
Investigators had no explanation to why the train was speeding or why it accelerated from 70 kmh to more than 100 kmh shortly before the derailment as a video recording from a camera installed on the train indicated.
Sumwalt said the train can only be accelerated by manual control but the NTSB is investigating whether a mechanical malfunction could also cause the train to accelerate.