A 12-car commuter train and a work train performing track maintenance were traveling the same direction when they “side-swiped” each other, causing the commuter train to derail and injuring 33 people, state officials said Sunday.

Gov. Andrew Cuomo, speaking at the site of the Saturday night accident, said initial reviews indicate the yellow maintenance train somehow entered the clearance space of the eastbound Long Island Rail Road train, causing it to derail and leaving “a splatter of yellow paint where the first collision occurred.”

“Both trains were running in the same direction — one was a work train, one was a revenue train and they side-swiped each other,” said Cuomo, a Democrat. “The question is why.”

Federal investigators from the National Transportation Safety Board were to determine what exactly caused the accident, Cuomo said.

Four people sustained serious injuries, including one passenger with multiple broken bones and a worker who suffered cuts, Metropolitan Transit Authority Chairman Thomas Prendergast said. Five Long Island Rail Road employees on the commuter train, and two on the work train, were among the injured, he said.

Craig Heller, one of 600 passengers aboard the LIRR train Saturday night, said his car started shaking suddenly after the collision.

“The car was shaking back and forth and back and forth,” he said. “We felt like we could actually completely tilt over while it was happening. That was a fear.”

Emergency workers used ladders to bring the injured off the derailed trail, which came to a stop on a stretch of tracks in a remote area on a hill about 22 miles east of New York City.

Workers were trying to clear at least one of the two tracks before the Monday morning commute, Cuomo said. The maintenance train had finished its track work Saturday night when it somehow violated the commuter train’s space, Prendergast said. The LIRR train was likely traveling faster than the work train when they collided, he said.

Long Island Rail Road trains have been involved in 72 accidents since Jan. 1, 2011, according to federal data, including 3 collisions and 15 derailments on tracks used for passenger service.

The derailment comes 10 days after another commuter train in New Jersey crashed into a terminal, killing one person and injuring more than 100.

(AP / YWN World Headquarters – NYC)