Inside the Derailed Amtrak Train

Dozens of the 238 passengers on board the New York City-bound Amtrak train that derailed in Philadelphia had to make their way through the flipped cars to get to safety.

Video shot by one of the passengers, Philadelphia-based MC Yameen Allworld, an associate of the soul band The Roots, shows the darkness and confusion that faced survivors as they tried to crawl out of the wreck.

"Crawl forward, sir," he is heard saying in a video that he posted on Instagram.

Another passenger can be seen crawling past what looks like the tipped hallway of a train car.

In a later video, Yameen shows cuts on both of his legs and neck.

Roots frontman Questlove posted a message on Twitter suggesting that Yameen had been celebrating his birthday but "thank god @yameenallworld is here to literally see another year," he wrote.

Former Congressman Patrick Murphy was also on board and told how he and several others near him escaped after pushing open an emergency window.

"People were pretty banged up, a lot of blood, a lot of bleeding, so I pulled myself up," Murphy told ABC News affiliate WPVI. "The guy I kind of landed on was okay. The guy next to him was completely passed out, unconscious."

Another passenger, Daniel Wetrin, was among more than a dozen people taken to an elementary school afterward.

"I walked off as if, like, I was in a movie," he told the AP. "There were people standing around, people with bloody faces. There were people, chairs, tables mangled about in the compartment ... power cables all buckled down as you stepped off the train."

The train's seven cars and the engine were derailed from the tracks shortly after 9:30 p.m. Tuesday. The Federal Railroad Administration reports that the engine of the train and two cars are upright, three are laying on their sides, one is nearly on it's roof and one is leaning dramatically.

While passengers in the other cars were able to walk out unaided, fire department officials had to use hydraulic rescue tools to help free those trapped inside.

Philadelphia Mayor Michael Nutter reported that there were at least five known casualties. Of the 55 reported injuries, six were deemed critical.

The cause of the crash has not been determined but a go-team of National Transportation Safety Board investigators has been dispatched to the scene.

Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here.