PHILADELPHIA — Daylight on Wednesday revealed the devastation caused by an Amtrak train derailment in Philadelphia that left at least six people dead and dozens injured, several critically, in a terrifying wreck that plunged passengers into darkness and chaos.

Some passengers had to scramble through the windows of toppled cars to escape. One of the seven cars was severely mangled.

Train 188, a Northeast Regional, was en route from Washington to New York with 238 passengers and five crew members when it jumped the tracks as it was rounding a sharp curve in the city’s working-class Port Richmond section shortly after 9 p.m. Tuesday, authorities said.

The accident closed the nation’s busiest rail corridor between New York and Washington as federal investigators from the National Transportation Safety Board arrived to begin examining the twisted wreckage and determine what went wrong.

“It is an absolute disastrous mess,” Mayor Michael Nutter said. “I’ve never seen anything like this in my life.”

Nutter confirmed five deaths and said not all the people on the train had been accounted for. Temple University Hospital said Wednesday a person died there overnight from a chest injury.

More than 140 people went to hospitals to be evaluated or treated for injuries that included burns and broken bones.

Amtrak said the cause of the derailment was not known.

Passenger Jillian Jorgensen, 27, was seated in the quiet car — the second passenger car — and said the train was going “fast enough for me to be worried” when it began to lurch to the right.