Metro-North Hudson Line service to the city resumed Wednesday morning at more than 98 percent as the investigation into Sunday's derailment is focusing more on the train's operator.
The Metropolitan Transportation Authority says that full Hudson Line service will be restored for the AM peak hours Thursday.
The MTA also told NY1 the engineer at the controls during Sunday's crash, William Rockefeller, is now on unpaid leave.
A former co-worker of Rockefeller told NY1 that the veteran engineer is somewhat of a "afternoon person" who was having a tough time adjusting to his new early morning shift.
The former co-worker said that Rockefeller made subtle comments that he liked afternoons better and that he was having trouble getting up early.
He said that even though Rockefeller was known as a reliable worker, he simply should not have been working at that time of day.
Dr. Steven Feinsilver, a sleep expert at Mount Sinai's Center for Sleep Medicine, wouldn't directly address this case but said that a pronounced shift in working hours can do a number on anybody's rhythms.
"You shouldn't assume that that's going to be easy, that people can just naturally shift from days to nights to evenings to whatever shift is necessary," Feinsilver said.
Rockefeller was said to be "losing his focus," suffering from "highway hypnosis" moments before the derailment.
Speaking with reporters Tuesday, a union official said Rockefeller "basically nodded" while at the controls on Sunday and applied the brakes too late to stop the crash.
"He had the equivalent of what we all have when we drive a car, and that is that sometimes, you have a momentary nod or whatever that might be. How long it lasts, I can't answer that. Only Billy can," said Anthony Bottalico with the Association of Commuter Rail Employees. "He caught himself, but he caught himself too late. He powered down, he put the train in emergency, but that was six seconds prior to derailment."
The National Transportation Safety Board removed the union from the investigation late Tuesday because of its comments to the media.
The NTSB says the Association of Commuter Rail Employees violated confidentiality rules.
The agency would not comment on Rockefeller's alertness at the time of the accident. But investigators say they found nothing wrong with the train's brakes, railway signals, or the track itself.
They also say tests on the train prior to the crash all checked out.
"We have determined that the Metro-North Mechanical Department performed a proper brake test prior to the train left station-no anomalies were noted. In addition, the crew conducted a running air brake test shortly after train left the station- again no anomalies were noted," said NTSB Board Member Earl Weener.
The NTSB says no alcohol was detected in tests on the train's crew members. They're still waiting for drug test results.
The resumption in Hudson Line service to Grand Central Terminal comes after crews worked around the clock to repair some 800 feet of damaged track.
The MTA says only one of the three damaged tracks has been repaired, and the other two tracks are still being fixed.
Despite the progress, a spokesman for the agency is asking commuters to be patient.
"Customers maybe should expect some delays today up to 15 minutes through congestion. We're funneling basically three tracks worth of trains into one, so there's gonna be some congestion here," said MTA Spokesman Aaron Donovan.
Metro-North riders who spoke with NY1 Wednesday morning at Grand Central Terminal seemed pleased with the service.
"Yesterday I had a roundabout route going to work, it took me about an extra hour so today it was great," said one commuter.
"It was great. Sad, unfortunate what happened last week but train's empty, people don't know its running," said another commuter.
"I'm really glad that they went to work and got it done really fast so, very surprised," said a third commuter.
Some Hudson Line riders said they were a bit nervous as they approached the scene of the accident while others said it did not phase them at all.
"They had so many people there you know the horse is out of the barn so everybody's watching so I didn't think there would be a problem today," said one commuter.
"Everybody was curious like looking at the scene but everything looked fine," said another commuter.