(NBC News) More than a day later investigators are still searching through the twisted metal, debris and battered rail cars after Sunday's fatal commuter train accident in New York.
The early thought is that speed played a factor in the deadly accident as investigators continue to examine the evidence and interview those on-board when the train left the tracks.
Today, massive cranes helped to upright and move the battered cars as investigators continue to search for why the metro north commuter train left the tracks killing 4 passengers and injuring more than 60.
"It could have been a problem with the track. It could have been quote unquote equipment failure. There were some rumors to that or it could have just been operator error human beings make mistakes," said New York Governor Andrew Cuomo.
NTSB investigators plan to talk with the driver and conductor of the train today.
The conductor has said there was a problem with the brakes as the train entered a sharp turn along the Harlem and Hudson Rivers.
The team is also now analyzing vital data from the black box recorder pulled from the wreckage.
"We'll know the speed of the train we'll also know what brake applications may have been as well as the throttle settings," said the NTSB's Earl Weener.
There were about 100 people riding the train at the time of the crash.
"A couple of people were hurt very badly right in front of me. Yeah....literally, the woman in front of me, her, ah, she was bleeding from her head pretty bad. And we really couldn't get out," said passenger Dennis O'Neil.
As many now begin to recover from their physical wounds doctors warn the mental scars could take much longer to heal.
"I think it's gonna be different for different people. We certainly have the ability to provide outpatient mental health and crisis counseling services here," said emergency room physician David Listman of St. Barnabas Hospital in the Bronx.
That's just part of what will be a long difficult recovery in the wake of the deadliest commuter train crash in New York in the last 20 years.
The investigation is going to take some time as well.
Teams will be on the ground here for a week to ten days; but determining the official cause of the accident could take a year or longer.
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