Amtrak Train Crash: Video Timeline of What We Know

Amtrak Northeast Regional Train 188 heading from Washington, D.C., to New York City derailed in Philadelphia on Tuesday night killing at least six people.

Officials say the investigation is still underway.

Here's what we know so far:May 12, 9:28 p.m.Amtrak Train 188 derails in Philadelphia. Six cars overturn in the crash, and the engine separates from the train, officials said.

Amtrak reports 238 passengers and five crew members were on board at the time of the incident.

11 p.m.Amtrak cancels all service between New York and Philadelphia.

"It is an absolute disastrous mess," Philadelphia Mayor Michael Nutter said. "Never seen anything like this in my life."

May 13The death toll climbs to six. Officials say the number of critical injuries is at least 10. Hundreds of people are treated at hospitals in the area.

Officials say they cannot confirm if everyone is accounted for, and fear more are dead in the wreckage.

The investigation is ongoing, but officials say the preliminary focus of the probe is on the speed of the train.

10:15 a.m.Nutter says the black box that has been recovered from the train is under analysis, and there is no information from it yet.

The train conductor was injured and treated, and is giving a statement to investigators, according to Nutter.

The NTSB is on the scene, looking into all facets of the derailment.

2:30 p.m.The death toll rises to at least seven people.

The site of the crash echoes an accident from 1943, when a Pennsylvania Railroad train crashed at Frankford Junction in Philadelphia. Seventy-nine people died and 117 others were injured. As the train traveled between Washington, D.C., and New York City, an overhead journal box overheated, causing one of the wheel axles to fail. Smoke and flames could be seen underneath the seventh car, but before workers could stop the train, the car jumped the tracks.

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