WASHINGTON — (CNN) A potentially key piece of evidence has been recovered in the hunt for what caused a deadly crash of a commuter train in New Jersey.

Investigators retrieved an event recorder from the New Jersey Transit train that hurtled past its stopping point Thursday at the Hoboken station and rammed through a passenger concourse, and they expect to download information from the device Friday morning, a US official with direct knowledge of the probe said.

Packed with passengers and traveling way too fast, the train slammed into a bumper block, went airborne and hit the concourse at about 8:45 a.m. during rush hour, killing a woman waiting on the platform and injuring more than 100 others.

The crash has indefinitely suspended New Jersey Transit train service to and from the Hoboken station, one of the busiest transit hubs in the New York area, forcing thousands of people to adjust their commuting plans.

New Jersey Transit posted a customer notice on its website advising commuters of their options until the damage can be assessed and repaired.

A separate train system, PATH, continues to run through Hoboken.

The train was at the end of a 17-stop route that had started more than an hour earlier in Spring Valley, New York. The Hoboken hub primarily serves the Lower Manhattan commuter market.

Images posted on social media showed part of the station’s roof had collapsed.

Witnesses described people helping bloodied passengers, some trapped by debris, from the packed front car.

Fabiola Bittar de Kroon, 34, of Hoboken, died after debris struck her while she stood on the platform, New Jersey Gov. Chris Christie said.

An additional 114 people were injured, he said.

The engineer, Thomas Gallagher, 48, was treated and released from a hospital.

Gallagher, who has been an employee of New Jersey Transit for 29 years, hasn’t yet spoken with National Transportation Safety Board investigators, the official with knowledge of the investigation said.

A neighbor, Tom Jones, told CNN affiliate WABC-TV that Gallagher said his childhood dream was to become an engineer. “Just a fine, fine family,” Jones said of the Gallaghers.

“Great next-door neighbors, wonderful kids, very caring people about others.”

The investigation will focus in part on speed and why the train didn’t stop well before the bumper block, a device meant to halt trains that pass their stops.

Also up for investigation, according to the NTSB: a train that overran its stop at the same station in 2011, injuring more than 30 people.

The NTSB also said it will consider whether a safety system called positive train control — which combines GPS, wireless radio and computers to monitor trains and stop them from colliding, derailing or speeding — might have prevented Thursday’s crash had it been installed.

New Jersey Transit has not yet installed positive train control, although it does use an older safety system.

Congress originally required the installation of the newer safety system by the end of 2015 but extended the deadline to the end of 2018.

The NTSB determined the probable cause in the 2011 crash of a PATH train at Hoboken as “the failure of the engineer to control the speed of the train entering the station.”

A contributing factor was “the lack of a positive train control system that would have intervened to stop the train and prevent the collision,” the agency said.

On Thursday, Christie and New York Gov. Andrew Cuomo cautioned people to wait until investigations are completed before concluding positive train control would have prevented the latest crash.

“That’s speculation that can only be based upon the cause of the accident, and until we know the cause of the accident were not going to be able to know what steps we can take in the future to avoid an accident like this,” Christie said.

Bhagyesh Shah, who rode in the front car on his way to work, said the train didn’t appear to slow as it entered the station.

“The next thing I know, I’m on the floor. We are plowing through something … and when the train came to a stop, I could see the parts of the roof on the first car and some of the debris next to me,” Shah said.

A New Jersey Transit worker at the station said he heard an explosion-like sound as the lead car, coming into the station fast, slammed into the bumper block.

“It went up and over the bumper block, through the depot … and came to rest at the wall by the waiting room,” worker Mike Larson said.

“It was going considerably faster than it should have normally been.”

Half of the first car was crumpled, and the roof crushed down to the seats, Larson said. The train should have stopped 10 to 20 feet before the bumper block, he said.

Passenger Leon Offengenden said he was in one of the cars behind the lead car when the crash happened.

“The front car is essentially off the rails … into the building of the station, with the roof sort of collapsed around it,” he said.

“The first car was just demolished. The train looked like it went through the stop,” Offengenden said.

“The first car looked like it catapulted onto the platform into the building. The roof collapsed. There was wire and water (and) everything.

“The lights went out and a few people screamed (when the crash happened).”

He said at first, he had no idea what was going on.

“I was sitting, but I couldn’t see the window. I didn’t notice that the train was going at an accelerated pace. It was just going,” Offengenden said.

“Now, looking back, I guess it didn’t slow down. It definitely didn’t slow down. There (were) no brakes. All of a sudden, it just crashed. Something happened obviously. … It’s the same feeling as when you get in a car crash.”

He said he left the train and “saw a man who had blood just running down his arm. He was wearing a suit and blood was just gushing.”

State officials have taken recent steps to improve rail safety.

In August, Christie signed a bill prohibiting an engineer from operating a New Jersey Transit train if his or her driving privileges are suspended or revoked due to a conviction for driving under the influence of alcohol or drugs or a related offense.

The law came after an engineer was found to have lost his license for 10 years due to DUI convictions.