Emergency personnel work at the scene of the train wreck in Philadelphia. Photo: Joseph Kaczmarek

Philadelphia - Dozens of people were injured on Tuesday after a regional train derailed near Philadelphia, with 10 cars overturned, firefighters said.

The Philadelphia Fire Department said it had sounded its fourth alarm, indicating a large-scale operation for passengers of Amtrak Train 188 travelling from Washington and bound for New York.

At least one of the metal train cars was bent in an L-shape.

Dozens of emergency personnel used torches to comb the area for survivors after dark. They used ladders to climb over the flipped trains.

Multiple fire engines, ambulances and police cars were deployed on the scene.

The fire department said it had requested helicopters for additional lighting.

Train 188, a Northeast Regional rail service train, was scheduled to leave Washington at 7.10pm (23h10 GMT) and arrive in New York at 10.34pm.

There are no seatbelts on trains operated by Amtrak, the national long-distance rail service.

The National Transportation Safety Board said it was gathering information about the derailment.

Former US Congressman Patrick Murphy of Pennsylvania was on the train.

“ I’m OK. Helping others. Pray for those injured,” he tweeted.

Murphy, who was on board the cafe car, said the train seemed to be going 60-70 miles (between 90km/h and 110km/h) when it suddenly derailed and rolled.

Some of the injured - many with bloodied hands and faces - were unable to move, Murphy said.