Investigators with the National Transportation Safety Board interviewed Friday the engineer of the Amtrak train that derailed in Philadelphia on Tuesday night. Investigators found engineer Brandon Bostian to be "extremely cooperative," said NTSB board member Robert Sumwalt.
Bostian told investigators he was not ill or tired, felt "fully qualified and ... reported no problems with his train handling," Sumwalt said.
He said he had "no recollection" of anything that happened once the train passed the North Philadelphia station, according to Sumwalt.
One of the assistant conductors on the train was also interviewed Friday and reported hearing radio transmissions that Bostian had with the engineer of a 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 (the Amtrak) engineer say something about his train being struck by something."
Sumwalt said there is damage to the lower portion of the Amtrak windshield that the FBI will examine as part of the investigation.
Investigators are learning more about the Amtrak crash which killed eight people, but they're still trying to determine what caused the train to speed up as it approached the curve.
CNN reports the NTSB is taking pieces of the train out of state.
Early this morning, crews loaded one of the train cars onto a trailer, and took it away.
It'll join other cars already transported to a rail yard in Delaware, as investigators work out the details of how the crash happened.
They won't get much help from Brandon Bostian, the engineer who -- initial data indicates -- was driving the train at more than 100-miles-per-hour in a 50-mile-per-hour curve when the train left the tracks, crashing and killing at least eight people.
Bostian has agreed to talk to NTSB investigators with his lawyer present, but his lawyer says Bostian doesn't remember much -- having suffered a concussion in the crash.
"Having the engineer speak would be helpful, but it's not essential," said Peter Goelz, Former NTSB Managing Director. "They have the physical facts. They have the event recorder. They'll be able to come up with a probable cause."
The NTSB says they have good quality video which shows the train accelerating as it approachesthe curve the curve, instead of slowing down. In the final 65 seconds of the video, the train goes from less than 70mph to 106 mph.
The question is, why?
A former co-worker calls Bostian a "great engineer."
(Drew Griffin/CNN) "Have you ever seen him drinking?"
(Xavier Bishop/Former Amtrak Assistant Conductor) "Never. "
(Drew Griffin/CNN) "Too sleepy?"
(Xavier Bishop/Former Amtrak Assistant Conductor) "No."
(Drew Griffin/CNN) "Texting?"
(Xavier Bishop/Former Amtrak Assistant Conductor) "No."
(Drew Griffin/CNN) "Phone calls?"
(Xavier Bishop/Former Amtrak Assistant Conductor) "Never had his phone on it didn't matter what the situation was never had his phone out."
With eight people dead and more than 200 injured, it is up to investigators to determine whether mechanical failure or human error is to blame.