(Corrects to show that only alcohol tests have come back negative; drugs test results are still pending)
By Mark Hosenball and Chris Francescani
Dec 3 (Reuters) - The driver of a New York commuter train that derailed on Sunday, killing four people, told investigators he "lost focus" and went into a daze shortly before the crash, according to a law-enforcement source.
A second source also briefed on the investigation said the driver, William Rockefeller, 46, lapsed into a "highway hypnosis."
The seven-car Metro-North train was traveling at 82 miles per hour (132 kph), nearly three times the 30-mph (48-kph) speed limit for the curved section of track where it crashed, investigators have said. The brakes were applied just seconds before it derailed.
The crash also critically injured 11 people and snarled travel for the roughly 26,000 regular commuters on the Metro-North Hudson line which serves suburbs north of New York City.
The National Transportation Safety Board (NTSB) has cautioned that its investigation would continue for weeks, if not months, and it was far from reaching a conclusion on the cause.
Alcohol tests on Rockefeller came back negative, and drug test results were still pending, NTSB member Earl Weener told a news conference on Tuesday.
The train might have benefited from a Positive Train Control (PTC) system to stop or slow a speeding train, Weener said.
"For more than 20 yrs, the NTSB has recommended implementation" of PTC, Weener said. "Since this is a derailment, it's possible that PTC could have prevented it."
Rockefeller, who has never been disciplined for job performance as train driver, has retained a defense lawyer, Jeffrey Chartier, who did not immediately respond to a Reuters request for comment. The NTSB was interviewing him on Tuesday afternoon, Weener said.
Rockefeller told investigators the train was operating normally when he somehow slipped into a daze, said the law-enforcement source, who has access to official reports on the investigation and requested anonymity.
Rockefeller told investigators he could not fully recall what happened, but that at some point he suddenly came out of the temporary daze, realized the train was going too fast and into a dangerous curve, and applied the brakes. It was too late to avoid the crash.
Law-enforcement agencies including the Bronx district attorney, the New York Police Department and transit police are monitoring the investigation.
If criminal charges are warranted, they would be brought by Bronx District Attorney Robert Johnson, a spokesman for Johnson said. (Additional reporting by Curtis Skinner; Writing by Daniel Trotta; Editing by Gunna Dickson)