The engineer of the Metro-North commuter train that derailed has told investigators he "zoned out" before the crash that killed four and injured 63 as the National Transportation Safety Board says they still not have found a problem with the brakes.

Emergency crews respond after Metro-North train derailed near the Spuyten Duyvil station (Christopher Gregory/Getty Images)

7 ABC reports engineer William Rockefeller was "not asleep, but he was not fully-there, either," said this source. "But it happened at the worst possible moment, on one of the most dangerous stretches of track on the system." When he realized he had zoned out Rockefeller "snapped back" to attention.

He told investigators, "I don’t know. I was in a daze,” according to the New York Post.

The NTSB yesterday said the train was going 82 MPH approaching the curve in the track in the Bronx that has a speed limit of 30 MPH.

At a press conference today, the NTSB said investigators hadn't found any evidence of brake or signal trouble during the train's nine previous stops. NTSB member Earl Weener said Tuesday there were "no anomalies."

While investigators had yet to finish talking with engineer William Rockefeller, questions swirled around him because the train went into the curve at nearly three times the speed limit. Dozens of people were injured.

As NTSB worked to determine what caused the Sunday morning wreck in the Bronx, Gov. Andrew Cuomo said Rockefeller should be disciplined for "unjustifiable" speed.

Rockefeller stayed out of sight. "This is a man who is totally distraught by the loss of life, and he's having a tough time dealing with that," said Anthony Bottalico, his union leader.

"Once the NTSB is done with their investigation and Billy is finished with his interview, it will be quite evident that there was no criminal intent with the operation of his train," Bottalico said.

Rockefeller, 46 and married with no children, has worked for the railroad for about 20 years and has been an engineer for 11, Bottalico said. Rockefeller lives in a well-kept house on a modest rural road in Germantown, N.Y., about 40 miles south of Albany.

Rockefeller's work routine had recently changed. He had begun running that route on Nov. 17, two weeks before the wreck, said Marjorie Anders, a spokeswoman for Metro-North's parent, the Metropolitan Transportation Authority.

Bottalico said Rockefeller had changed work schedules — switching from afternoons to the day shift, which typically begins at 5 a.m. — but was familiar with the route and qualified to run it.

In case of an engineer becoming incapacitated, the train's front car was equipped with a "dead man's pedal" that must be depressed or else the train will automatically slow down, Anders said.

New York Governor Andrew Cuomo (D) told New York radio station WNYC that since the NTSB's initial investigation has determined speed was major factor in Sunday's derailment that "this is now a very serious situation." Cuomo added "we want to make sure that the MTA riders are safe and this operator is not going be operating a train anytime soon, that I can assure you. But there will be a process and he has rights and other agencies may want to take a look at possible degrees of liability also."

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The Associated Press contributed to this report.