Washington (CNN)Amtrak train engineer Brandon Bostian told investigators he doesn't remember anything prior to last year's Philadelphia crash that killed eight passengers and sent more than 200 to the hospital, according to documents made public Monday.
Amtrak 188 driver: 'I don't remember anything' before crash
"I don't remember anything particularly out of the ordinary," he said, according to the transcript of his conversation with investigators of the Amtrak 188 crash. "Unfortunately, the last memory I have on the way back is approaching and passing the platforms in North Philadelphia. I remember turning on the bell, and the next thing that I remember is when I came to my senses I was standing up in the locomotive cab after the accident."
The National Transportation Safety Board (NTSB) released more than 2,000 pages of documents as part of the agency's ongoing investigation into the May 12, 2015, crash including interview transcripts with the 32-year-old engineer.
While the fact-finding portion of the investigation is complete, NTSB investigators are still analyzing all the evidence. The agency has not yet determined an official cause for the deadly derailment of Amtrak 188. That will happen later this spring when the agency releases its final report.
The working theory is that Bostian became distracted by radio chatter from other train operators discussing being hit by some sort of projectile, a source close to the investigation told CNN.
At least two other trains -- a regional Southeastern Pennsylvania Transportation Authority train and an Amtrak Acela -- reported being struck with projectiles in the area near the crash site. NTSB documents reveal the FBI did a chemical and visual examination of the window from the Acela train and found no indication a bullet caused the damage to the train's window. That means some other projectile was at fault.
Data shows Bostian applied the train's full emergency brakes just moments before the derailment.
Bostian also told investigators he dialed 911 immediately following the crash.
"I got my cellphone out of my bag. I turned it on. When it came on, while it was powering up, I think I got off the engine and walked towards some passengers that I heard. When the phone came on, I turned off airplane mode, and then when it reconnected with the network, I called 911 and I said that the -- that a train had derailed. And at the time I did not know what my location."
Bostian said he did not recall any mechanical problems with the train at the start of the trip. The only issue Bostian said he noticed was minor -- excessive wind noise outside the engineer side window.
The Amtrak passenger train was traveling from Washington to New York City when seven of its cars and its engine jumped the rails. The train's data recorder revealed it was traveling at 106 miles per hour around a sharp curve that had a speed limit of 50 mph.
Other documents also released by the NTSB said medical professionals who examined Bostian after the crash said he told them he remembered feeling the train swerve, falling out of his seat and then thinking "it must be a dream."
According to documents, medical personnel wrote "Bostian believes he kept his hands on the wheel at the time of the accident, and thinks he was able to get out of the train on his own."
Doctors diagnosed Bostian with an acute head injury, a left knee laceration, a facial laceration, a sprain of the right knee and multiple abrasions. Bostian's blood and urine were tested after the crash, but nothing illegal was detected. The only substance detected was Lidocaine, an anesthetic agent used to numb the engineer for sutures in the hospital.
Phone records indicate Bostian was not using his cell phone for calls, texts or the Internet while he was operating the train and Amtrak's records also show that the engineer didn't use the train's Wi-Fi system.
The train's locomotive was built by Siemens and delivered to Amtrak in 2014 specifically for its Northeast Corridor service, according to a Siemens official. That makes it fairly new, and NTSB investigators found no issues with the train's engine. The railroad signals were also all found to be functioning properly as well.
The Washington-New York corridor is the busiest stretch for Amtrak nationwide. Hundreds of trains, carrying thousands of passengers, have made that trip in recent years, most of them rolling seamlessly from start to finish on a roughly 3½-hour journey.
The section of track where the train derailed in Philadelphia is Frankford junction, located between Washington and New York.
Frankford Junction was not equipped with safety equipment called automatic train control. The automated system notifies an engineer if the train is speeding and applies the brakes automatically if the engineer does not respond. The NTSB has said had that equipment been installed the accident would not have happened.
Amtrak has since installed that speed control along the section of track where the derailment occurred.