FAIRFIELD, Conn. (AP) — Two commuter trains serving New York City collided in Connecticut during Friday's evening rush hour, injuring about 50 people, authorities said. There were no reports of fatalities.

The Metro-North Railroad, a commuter line serving the northern suburbs, referred in a news release to a "major derailment" near Fairfield, just outside Bridgeport. It said emergency workers were at the scene of the accident, which came shortly after 6 p.m.

Bill Kaempffer, a spokesman for Bridgeport public safety, told The Associated Press approximately 49 people were injured, including four with serious injuries. About 250 people were on board the two trains, he said.

Photos taken at the scene showed a train car askew on the rails, with its end smashed up and brushing against another train. Amtrak suspended service indefinitely between New York and Boston.

"At this stage, we don't know if this is a mechanical failure, an accident or something deliberate," Fairfield police spokesman Lt. James Perez told the Connecticut Post.

The railroad said a train that departed New York City's Grand Central station en route to New Haven derailed. A westbound train on an adjacent track then struck the derailed train. Some cars on the second train also derailed as a result of the collision.

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.

"Everybody seemed pretty calm," he said. "Everybody was thankful they didn't get seriously hurt. They were anxious to get home to their families."

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.