11:46 p.m. ET: At least 49 people were hospitalized, including six who were critically wounded, authorities said.
11:41 p.m. ET: At least five people are dead, Philadelphia Mayor Michael Nutter said. Seven cars and engines in “disarray” – turned over, upside down, he said. “It is an absolute, disastrous mess.”
11:24 p.m. ET : There were approximately 238 passengers and 5 crew members on board, Amtrak said.
As day broke in Philadelphia on Wednesday, rescue workers were still searching inside the mangled wreckage of an Amtrak train that derailed the night before, killing at least six people and sending another 150 to various hospitals.
At least five people died and about 50 hospitalized, including six in critical condition, authorities said. The train was carrying 238 passengers and 5 crew members.
“It is an absolute, disastrous mess,” Philadelphia Mayor Michael Nutter said of the crash site. “I’ve never seen anything like this in my life.”
The Amtrak Northeast Regional Train 188 was traveling from Washington to New York when it derailed north of the city of Philadelphia, Amtrak said. The cause wasn’t immediately known.
“We do not know what happened here. We do not know why it happened,” Nutter said. There was no indication the derailment was a result of an impact with another train, he said.
Firefighters arrived to find seven cars and the train’s engine either turned over or upside down. Some passengers were able to escape safely. Crews had to cut through the cars to get to others.
“This is a nightmare and it can’t be happening,” passenger Joan Elfman told CNN affiliate KYW. “There are many, many injured people.”
The moment of impact
Word of the derailment quickly spread on social media, with posts on Twitter describing crews searching for wreckage and helicopters hovering overhead.
Philadelphia police asked area residents to not crowd to the scene.
Former Congressman Patrick Murphy said on Twitter that he was aboard the train when it crashed. “Helping others,” he said. “Pray for those injured.”
Later he shared a photo that showed a firefighter inside the train.
On Instagram, another passenger posted video of what appeared to be a rescue in progress.
Amtrak shut down rail service between Philadelphia and New York City for the night. It set up a special number for those seeking information on friends and family aboard the train: 1-800-523-9101.
CNN’s Kevin Conlon contributed to this report.