Train speeding before deadly crash: US officials

Federal investigators have confirmed that preliminary data showed the Amtrak train which derailed on Tuesday night near Philadelphia was travelling at more than 100 miles an hour (161 kilometers), or around twice the speed limit.

The death toll now stands at seven, with around 10 people still in hospital in critical condition.

Experts from the National Transportation Safety Board (NTSB) are continuing to examine the twisted wreckage of the Amtrak train for any signs of what may have caused the accident.

The train went off the tracks as it approached a sharp curve near Philadelphia along the northeast US rail corridor between Washington and New York, at around 9:30 p.m. local time. Its black box has since been recovered and sent for analysis.

Death toll could rise

Authorities said not all of the 243 passengers and crew believed to have been onboard the passenger train had yet been found, warning that the death toll could increase. They were working to match the passenger manifest with the list of injured, and called on people who may have left the scene to contact Amtrak. Some passengers on the list may also have not boarded the train, further skewing the numbers.

Philadelphia Mayor Michael Nutter cautioned that it might be a while before the cause of the crash was discovered.

"We'll get to the bottom of it and figure out what happened, why it happened, but that will take some time," he said.

Emergency official Sam Phillips said the city's hospitals had treated "over 200 patients last night and this morning," including the train's conductor and engineer.

Many of the injured are believed to have suffered broken bones.

One of those killed was a midshipman on leave from the US Naval Academy in Maryland, and an Associated Press staffer.

NTSB investigator Robert Sumwalt said officials would go over "the track, the rail signals, the operation of the train, the mechanical condition of the train [and] human performance."

He said first responders were searching the remains of the train to make sure no one else was inside.

Witnesses described train cars tumbling, with people and debris thrown around inside.

Firefighters reported hydraulic equipment had to be used to cut open carriages, while former Pennsylvania congressman Patrick Murphy, a passenger on the train, said others kicked out windows to escape.

One of the train's seven cars landed upside down and three had come to rest on their sides.

Train service suspended

US President Barack Obama sent his sympathies to the accident victims on Wednesday, calling it "a tragedy that touches us all."

Trains between Philadelphia and New York will likely be suspended for the rest of the week.

The incident is the latest in a string of accidents on busy rail routes in the US, raising questions over the state of the country's rail infrastructure.

an/cmk (dpa, Reuters, AFP, AP)