HOBOKEN, New Jersey (WASHINGTON POST) - Federal investigators are assessing whether equipment failure, an incapacitated operator or other factors could have caused a packed commuter-rail train to barrel into Hoboken Terminal and slam into the station in a rush-hour crash that killed one person and injured more than 100 others.

New Jersey Governor Chris Christie said the operator of the train, who was hospitalised and later released, was cooperating with the investigation. He will be interviewed by National Transportation Safety Board (NTSB) officials in coming days.

Mr Christie said the crash on Thursday (Sept 30) appeared to be accidental. Officials declined to speculate on a cause, but one thing was clear: The train was travelling far too fast as it entered one of the busiest transportation terminals in the New York area, crashed onto the concrete platform, destroyed the metal canopy over the platform, and finally came to a rest when it crashed into the station building.

"When you see the destruction up close, the silver lining is that there's only been one fatality," said New York Governor Andrew Cuomo. "Because the destruction is significant. And the power of the train coming in is obviously devastating in its impact."

Ms Bella Dinh-Zarr, vice-chairman of the National Transportation Safety Board, said the speed limit on the track entering the station is 10 mph.

Ms Dinh-Zarr, who is part of the NTSB team in Hoboken, said one question investigators will be examining is whether positive train control (PTC), a federally mandated technology designed to automatically apply emergency brakes to runaway trains, could have prevented the crash. The NTSB has advocated for the technology for 40 years, she said.

Railroads were required to adopt PTC by last December, before Congress passed a law allowing railroads to delay installation for three to five years.

New Jersey Transit has not installed PTC on any of its trains, according to data maintained by the Federal Railroad Administration. Safety experts said the crash also raised questions about how the train's basic safety systems functioned.

New Jersey Transit said earlier this year that its entire network is equipped with an Automatic Train Control system. Such systems are meant to slow or stop a train in certain circumstances.

"People have to look and see exactly how New Jersey Transit has implemented that system on that track and how far it extends into the terminal," said Mr Steven Ditmeyer, a former Federal Railroad Administration official. Such Automatic Train Control systems are a blunter, and less sophisticated tool than the newer PTC systems.

Mr Ditmeyer noted, however, that it's hard to know precisely how PTC would have worked in this case. "The Federal Railroad Administration rules on positive train control grant an exemption for terminals," he said, though they are notoriously complicated environments.

The train had been traveling from Spring Valley, New York, to Hoboken Terminal, a bustling transit hub that serves four different passenger rail systems, along with a water ferry. Passengers described the moments before impact, as they looked out their train's window at around 8.45am local time and realised that the train - which usually slows to a crawl as it enters the stations - hurdled through the railyard and into the terminal.

Accountant Jim Finan was sitting toward the rear of the first car when he realised the train was coming in much too fast."We were getting to the platform, but we were still at full speed," Mr Finan, 42, said. "The train didn't slow down at all."

He recalled there came a loud "boom" as he felt the train hit the barrier, burst onto the platform, blasted through the support beams holding up the platform's metal canopy and careened toward the station building.

"We were just bouncing as we went across the concourse," he said. "The only thing that stopped the train is the fact that it slammed into the building."

An average of 60,000 people travel through the station every day.

Mr Alex Moaba of Millburn, New Jersey, was on a Hoboken-bound train that pulled into the terminal minutes after the crash, before emergency personnel had arrived. He said part of the ceiling was dangling - the first indication that something had gone wrong.

"We were just piecing together what had happened," he said. "I thought to myself 'maybe a display board had fallen.' I looked a little closer and saw that a train was literally in the middle of the station, off the tracks."

"It was kind of eerily quiet and calm," he added.

Videos and photos taken by passengers from the moments after the collision showed a nightmarish scene: The platform covered in twisted metal and debris from the collapsed roof as station staff peered into the train and passengers and bystanders began yelling and shrieking, some of them trapped under the wreckage.

People were bleeding profusely from cuts to their head, Mr Finan said, and one man seemed to be holding his severed thumb in place. Others had cuts on their hands. Mr Finan pulled off the rubber around an emergency-exit window and another man pushed the window out. They both helped two women crawl out of the train before New Jersey Transit workers began opening the doors.

The New Jersey State Medical Examiner identified the crash victim as Ms Fabiola Bittar de Kroon, 34, of Hoboken. She was standing on the platform at the time of the crash and was killed by the debris that fell from the metal canopy, Mr Cuomo said.

The NTSB dispatched a team of two dozen people, with specialties ranging from mechanics and track signal systems to train operations and survival factors. The head of the Federal Railroad Administration and New Jersey's attorney general are also investigating the crash.

Ms Dinh-Zarr said investigators have so far been prevented from accessing the cab car at the front of the train because metal debris from the canopy has fallen onto the front part of the train. Because of the age of the building, there are also concerns about asbestos.

"I want to emphasise that we will only proceed to inspect the cars when it's safe to do so," Ms Dinh-Zarr said. "It may be tomorrow afternoon before we can safely do that."

Once the debris is clear, they intend to retrieve event recorders and video cameras installed in the front and the back of the train. The event recorder will provide information on the train's speed in the moments before the crash, as well as whether the operator activated the brakes. They will also be investigating whether the alerter in the cab of the train was activated in the moments before the collision. The device automatically sets off an audible or visual alarm after a predetermined number of seconds go by with no activity detected from the train's operator.

There was a bumper at the end of the station's tracks designed to absorb the impact of a train that has overrun the tracks, but it likely would not have done much to halt the speeding train.

"Even if you have an energy-absorbing system, it's going to be designed for 5 to 7 miles per hour," said Mr Allan Zarembski, director of the Railroad Engineering and Safety Program at the University of Delaware. "If you're going 15 to 20 miles per hour, that would be beyond the speed capability for any end-of-track device."

Ms Dinh-Zarr said investigators will examine similarities between this and a similar crash in May 2011 involving a PATH commuter-rail train that hit the bumpers and injured more than 30 people, including the engineer and the conductor.

After that incident, an NTSB investigation determined that the engineer failed to slow down as the train entered the station. It wasn't until two seconds prior to the collision that the engineer applied the brakes. Investigators estimated the train was going 13 mph when it hit a barrier that is intended to stop trains.

The NTSB concluded that PTC could have prevented the crash.

NTSB investigators also determined that positive train control could have prevented a May 2015 Amtrak wreck, in which eight passengers died and 159 were injured outside of Philadelphia. In that case, the technology had been installed on the train, but not yet activated.

Under the technology system, computer software can automatically apply the brakes to a train if an operator is unresponsive, or if the train exceeds the speed limit along a certain segment of the tracks. It is costly and complicated to install, which has led to feet-dragging from passenger train systems and freight railroads around the country.

"PTC has been one of our priorities," Ms Dinh-Zarr said on Thursday, moments before she boarded an NTSB airplane to fly to the crash site.

"We know that it can prevent accidents. Whether it is involved in this accident, that is definitely one of the things that we will look at carefully."