PHILADELPHIA (REUTERS, AFP) - The engineer of the Amtrak train that crashed in Philadelphia told investigators that he did not feel fatigued or have any illness before the accident, a National Transportation Safety Board official said on Friday.

The official, Robert Sumwalt, told a news conference that the engineer, Brandon Bostian, was "extremely cooperative" during a 90-minute interview but that he did not remember anything of Tuesday's crash that killed eight people.

Sumwalt said the engineer is a longtime employee of Amtrak with years of experience at the controls of the train that traveled along the corridor - the busiest route for the US railway.

Bostian, 32, started working with Amtrak in 2006 as a conductor, and became an engineer in 2010.

"Since 2012, he has worked out of New York City. And he's been on this particular job for several weeks," said Sumwalt.

"He works five days a week. It's an out and back trip for him. New york, Washington, and back to New York. Five days a week," Sumwalt said.

He added that routine drug and alcohol testing were performed on the engineer by Amtrak, as is always the case following an accident.

"We're waiting on the results of those tests," the NTSB official said.

The federal transportation agency is leading the investigation into the cause of the crash, one of the worst in years involving a US passenger train.

Amtrak Train 188 was traveling from Washington to New York when it crashed as it entered a curve while moving at a little over 160kmh - more than twice the speed limit, according to investigators.

Video leading up the crash shows the train accelerating as it nears the curve, rocketing from 70mph to over 100mph in the minute or so before the footage cuts out.

Eight of the train's 243 passenger and crew were killed and dozens injured in the crash that saw some train cars overturned others reduced to heaps of twisted metal.