The engineer of the train that derailed on Sunday is said to have "dozed off" moments before the accident. William Rockefeller was driving the train through the Bronx in New York when he came upon a 30 mph zone going 82 mph.

Fox News reported that Association of Commuter Rail Employees (ACRE)'s general chairman, Anthony Bottalico, explained, "He basically nodded…He had the equivalent of what we all have when we drive a car--that is, you sometimes have a momentary nod."

Rockefeller's attorney, Jeffrey Chartier likened the doze to a phenomenon known as highway hypnosis.
"He caught himself, but he caught himself too late," Bottalico said.

READ ALSO: Bronx Metro Derailment: Federal Investigation Underway

According to the Telegraph, Rockefeller was on the second day of a five-day work week and had reported for duty around 5 a.m. following a normal nine-hour shift the day before.

National Transportation Safety Board member, Earl Weener, said, "There's every indication that he would have had time to get full restorative sleep."

Blood tests revealed that Rockefeller had no alcohol in his system and the investigation is underway regarding the details surrounding this accident that left four dead and more than 60 injured.

Contact Executive Producer Kaysie Ellingson here.