(Bloomberg) -- At least five people were killed Tuesday night,and dozens of others injured, when an Amtrak train headedto New York City derailed in Philadelphia, shutting down part ofthe busiest passenger rail corridor in the U.S.

Northeast Regional Train 188, which originated inWashington, went off the tracks about 9:30 p.m., sending more than50 people to hospitals for treatment, according to the city’s firedepartment. The cause wasn’t immediately known.

An engine and seven cars careened off the tracks, according toKevin Thompson, a spokesman for the Federal RailroadAdministration. Three cars were resting on their sides and onealmost on its roof. One car was perpendicular to the others.

The wreck turned a Philadelphia neighborhoodinto a search and rescue zone, illuminated by flashlights andspotlights as rescue workers pulled the injured from cars and triedto determine whether other people remained trapped. Bloodiedpassengers could be seen hobbling from the wreckage.

Right: Emergency personnel help a passenger at thescene. (AP Photo/Joseph Kaczmarek)

The train, which derailed in the northeast section ofPhiladelphia, carried about 238 passengers and five crew, accordingto Amtrak.

Philadelphia Mayor Michael Nutter confirmed the dead at a newsconference. “It is an absolute, disastrous mess,” Nutter toldreporters Tuesday night. “We do not know why this happened.”

Passenger Traffic

Amtrak service between New York and Philadelphia is suspended,promising to send business travelers and commuters searching forother ways to get up and down the East Coast.

However, modified service will be provided on Wednesday betweenWashington and Philadelphia, Harrisburg and Philadelphia, and NewYork and Boston, according to an Amtrak statement. In addition, NewJersey Transit will honor Amtrak tickets between New York City andTrenton.

Ridership in the Northeast Corridor on regional and Acela trainsbetween Washington and Boston rose to 11.6 million in the fiscalyear that ended Sept. 30, up 3.3% from the prior year, according tothe railroad.

The derailment was in an area called FrankfordJunction that has a large curve, according to the Associated Press.The AP reported that a 1943 derailment of the CongressionalLimited, which killed 79, occurred nearby.

Left: Emergency personnel work to save passengers from thewreck. (AP Photo/Joseph Kaczmarek)

The National Transportation Safety Board is sending a team toinvestigate the accident, the agency said on Twitter. The team willarrive in the morning.

The Federal Railroad Administration sent a team of eightinvestigators and the agency’s acting administrator, SarahFeinberg, according to an agency statement.

The derailment was far from Amtrak’s deadliest accident. In1993, 47 people died and 103 were injured as rail cars careened offa bridge and into water near Mobile, Ala.

Tuesday’s mishap occurred in Philadelphia’s Frankfordneighborhood in an area filled with industrial warehouses, automechanics and body shops.

‘Big Flash’

Michelle Premaza, 33, who lives a quarter-mile away, said shewas in her house when the crash occurred. She said she saw andheard the impact.

“I seen a big flash and heard rolling thunder,” Premaza said.“It was crazy.”

Another resident, Leslie Painter, 49, said she saw busescarrying victims away from the scene.

“This is scary,” Painter said. “I’ve lived here my entire lifeand there’s never been no accidents like this.”

The AP reported that one of its managers, Paul Cheung, who wason the train, said it started to slow just before thederailment.

“Then suddenly you could see everything starting to shake,” theAP quoted him saying. “You could see people’s stuff flying overme.”

Former Representative Patrick Murphy of Pennsylvania was aboardthe train when it crashed and helped passengers out ofthe wreckage, according to messages and photos he posted onTwitter.

--With assistance from Romy Varghese inPhiladelphia.

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