Investigators previously revealed the train entered the curve at 78 mph. The speed limit in the area of bend is 30 mph.
Three people were killed and 70 were injured when the train, on its inaugural revenue run, derailed, leaving some train cars dangling off a bridge over Interstate 5 in DuPont.
Investigators were unable to interview the engineer, a 55-year-old male, until mid-January due to the seriousness of his injuries. In the interview with the NTSB, he said he performed as many as 13 qualifying trips on the route in the five weeks preceding the opening of the new service.
He said he felt rested and alert before the start of his shift on the day of the accident and was aware of the 30 mph speed restriction on the curve just prior to mile marker 20.
The engineer recalled passing mileposts 16 and 17, but not 18 or the 30 mph advance speed sign ahead of the curve.
A qualifying conductor was present in the locomotive at the time of the derailment, but the engineer said it was not a distraction and there was minimal conversation.
Positive Train Control was not activated on the tracks at the time of the derailment.
An Amtrak spokesperson told ABC News they are cooperating with the NTSB investigation.