Two commuter trains collided in Connecticut last night, sending 60 people to hospital, including five with critical injuries.
Officials said about 700 people were on board the Metro-North trains when one, heading east from New York City to New Haven, derailed about 6.10pm just outside Bridgeport.
It collided with another train, heading west from New Haven to New York on an adjacent track. Some cars on the second train also derailed as a result of the collision.
Amtrak, which uses the same rails, suspended service indefinitely between New York and Boston.
One passenger, Jason Brown, told ABC News: "I could see part of the train in front of me curving and I was like, 'that's not right, I shouldn't be able to see that.'
"My immediate instinct was to get up and brace myself because I could see we were going towards whatever derailment had happened.
"And the next thing I knew I was in the air."
Another passenger - Lola Oliver, 49, from Bridgeport - said she was riding one of the trains when the crash threw her from her seat.
She told The Associated Press: "All I know was I was in the air, hitting seats, bouncing around, flying down the aisle and finally I came to a stop on one seat. And I just gripped it because I felt the train sliding."
Investigators did not know what caused the first train to derail last night. Connecticut governor Dan Malloy said there was no reason to believe it was anything other than an accident. The National Transportation Safety Board was sending a team to investigate.
"We're most concerned about the injured and ultimately reopening the system," Malloy said from the scene about three hours after the crash.
The governor said that most people were not seriously hurt. Among those critically injured, he said, one's injuries were "very critical."
The Metro-North Railroad, a commuter line serving the northern suburbs, described it as a "major derailment." Photos showed a train car askew on the rails, with its end smashed up and brushing against another train.
Malloy said there was extensive damage to the train cars and the track, and it could take until Monday for normal service to be restored. He said the accident will have a "big impact on the Northeast Corridor."
By late evening, Bridgeport Police Chief Joseph Gaudett said everybody who needed treatment had been attended to, and authorities were beginning to turn their attention to investigating the cause.
The Metropolitan Transportation Authority operates the Metro-North Railroad, the second-largest commuter railroad in the nation. The Metro-North main lines — the Hudson, Harlem, and New Haven — run northward from New York City's Grand Central Terminal into suburban New York and Connecticut.