The FBI has ruled out foul play in their investigation into Friday night's rush hour train crash in Connecticut that injured 72 people.

National Transportation Safety Board officials are looking into a broken part of the rail that underwent repairs last month, but have not determined whether it was a pre-existing fracture or if it occurred as a result of the accident, according to NTSB spokesperson Earl Weener, who provided an update at a news conference on Saturday afternoon.

Meanwhile, one man with serious head injuries is awake and talking, said Connecticut Sen. Richard Blumenthal, who spoke to patients at St. Vincent Hospital. The train conductor, who helped several riders off the train before being transported, remains hospitalized with a lower back injury.

NTSB officials arrived on the scene on Saturday morning to begin investigating the cause of the train crash, injuries sustained by the commuters and operator performance.

Connecticut Gov. Dannel Malloy and other officials spoke at a news conference on Saturday morning where they described a grisly scene after a Metro-North commuter train heading east from New York City derailed and was hit by an oncoming train heading west from New Haven.

"The damage is absolutely staggering," Sen. Blumenthal said. "Ribbons on the sides of cars are torn away like ribbons of clothes."

The NTSB's investigation could take seven to 10 days but that does not mean that service shutdown will take that long, board spokesman Earl Weener said..

The eastbound Metro-North train derailed just after 6:00 p.m. and was hit between the Bridgeport and Fairfield stations, officials said.

"We came to a sudden halt. We were jerked. There was smoke," Alex Cohen, a Canadian passenger on the westbound train en route to New York, told NBC Connecticut.

"People were screaming; people were really nervous. We were pretty shaken up. They had to smash a window to get us out," he said.

St. Vincent Hospital in Bridgeport, Conn. said on Saturday that it saw a total of 46 patients, six of whom were admitted for treatment. All patients remained in the hospital and were reportedly in stable condition.

Bridgeport Hospital saw 26 patients and admitted three. Two of those patients were in critical condition a day after the accident, and one was in stable condition, according to The Associated Press.

It was not immediately clear what had caused the derailment.

"I have no reason to believe this is anything other than an accident," Gov. Malloy said Friday night.

Chaos Along the New Haven Line

Malloy warned Friday that the crash had caused extensive track damage along one of the nation's busiest corridors, and commuters throughout the Northeast could face difficult travel in the days ahead.

Eastbound Metro-North service is disrupted at South Norwalk, while westbound service is suspended past Bridgeport.

On Friday, the collision roiled the weekend commute for a wave of workers heading home from New York — not just the hundreds of passengers on each of the trains that collided, but hundreds more on the trains behind them.

The small South Norwalk station was a chaotic scene in the minutes just after the crash, as hundreds of passengers scrambled — many of them in vain — to hail cabs to complete their trips home.

Service Disruptions Could Last Days

Amtrak service between New York and New Haven will be suspended through Sunday, according to a press release, and there is no estimate on what time service will be restored. There is limited Northeast Regional service available between Boston and New Haven.

That was largely, officials said, because two of the four tracks in the segment of the rail line were already out of service for long-term improvement projects.

Normal service was not expected to resume until a full investigation was made, the track fully assessed and repairs made. That could take some time, since the train cars can't be removed until after an investigation, and since they must be removed by crane, the MTA said in a statement.

Stay with NBC Connecticut for more updates on this developing story.