NOTE: Those trying to contact passengers on the train should call the Amtrak Hotline at 1-800-523-9101.
An Amtrak train abruptly overturned in Philadelphia, killing at least six people and injuring dozens of others, some of whom had to scramble through the windows of toppled cars to escape.
Train 188, a Northeast Regional, left Washington, D.C. and was headed to New York when it derailed shortly after 9 p.m. Tuesday. Amtrak said the train was carrying 238 passengers and five crew members.
Five people are listed in critical condition and 140 were taken to area hospitals to be evaluated or treated, officials said. One of the 54 patients brought to Temple University Hospital Tuesday night died at the hospital, Chief Medical Officer Dr. Herbert Cushing announced early Wednesday. The other hospitals have not released an update on their patients.
Witnesses said the scene of the derailment was horrific, with cars "completely overturned, on their side, ripped apart," Philadelphia Mayor Michael Nutter said. One car came to rest perpendicular to the tracks, officials said.
Chopper video from the scene showed train tracks twisted underneath the cars. Passengers could be seen fighting their way out of the cars and milling in groups near the train.
"It is an absolute, disastrous mess," Nutter said.
Rescuers struggled overnight Tuesday to determine how many casualties there were in the wreckage. Officials stressed the final number of casualties was preliminary and may change.
Officials have not yet released the identities of the dead.
"I've never seen anything so devastating," said Philadelphia Fire Department Deputy Commissioner Jesse Wilson. The cars are "in pretty bad shape. You can see that they're completely, completely derailed from the track. They've been destroyed completely. The aluminum shell has been destroyed and they've been overturned completely."
The crash required a 4-alarm response, including 120 firefighters and 200 police officers.
The six cars derailed in Port Richmond, a working-class part of Philadelphia's Great Northeast.
Witnesses said the train was going into a turn when it shook. People were thrown to the ground, "chairs inside the train became unscrewed and suitcases were falling on people," said Max Helfman, 19, of Watchung, New Jersey, who was on the train with his mother.
"My mother flew into me and I literally had to catch her," he said. "People were bleeding from their head. it was awful."
The cause of the crash remains unknown.
The National Transportation Safety Board said Tuesday night that it had launched a "go team," a specialized team of investigators, to arrive at the site of the crash Wednesday morning.
"We do not know what happened here," Nutter said. "We do not know why this happened. We are not going to speculate about it."
Amtrak service between New York and Philadelphia is suspended, Amtrak said late Tuesday. Amtrak did not estimate when it would resume.
Paul Cheung, an Associated Press employee who was on the train, said he was fortunate to be at the back of the train, and the front of it looked "pretty bad."
Former Congressman Patrick Murphy was on the train in the cafe car and said he helped people off the train.
"It wobbled at first and then went off the tracks," he told MSNBC's Lawrence O'Donnell. "There were some pretty banged-up people. One guy next to me was passed out. We kicked out the window in the top of the train car and helped get everyone out."
He tweeted photos of firefighters helping people in the wreckage.
A few of the injured could not move, Murphy said, and one person required a stretcher.
"Pray for those injured," he said. He said he suffered a cut to his leg but is OK.A producer for NBC Nightly News said she was in the rear of the train when it derailed. "I was in complete shock. I think most people were," said Janelle Richards. "Our first thought was, 'How do we get off of this car?' That was the first thing I heard out loud."
Richards said a woman in the aisle had blood running down her face. However, she added, a minority of the people in the car were injured.
Richards' car did not flip over as Murphy's did. Someone had figured how to open a door enough to climb through, and that passenger helped passengers exit the train.
Police swarming around the crash site told people to get back, away from the train.
Passengers quickly retreated from the train tracks because they were afraid the overhead electrical poles were going to collapse inward, Richards said.
"I remember an Amtrak employee saying 'Don't stay near the tracks, don't stay near the tracks,'" Richards said. "The thought that another train could be coming was the scariest thought."
In a video posted on Instagram, passengers are heard telling other victims to crawl forward.
Local resident David Hernandez, whose home is close to the tracks, heard the derailment.
"It sounded like a bunch of shopping carts crashing into each other," he said.
The crashing sound lasted a few seconds, he said, and then there was chaos and screaming.
Federal Railroad Administration records show there have been nine Amtrak derailments so far in 2015, compared to 28 in all of 2014 and 25 in 2013.
Another Amtrak train, bound for New Orleans, crashed on Sunday. That train struck a flatbed truck at a railway crossing in Amite, killing the truck's driver and injuring two people on the train.
In March, at least 55 people were injured when an Amtrak train collided with a tractor-trailer that was stuck on the tracks in North Carolina.
Stay with News4 Today and NBCWashington for updates.