An Amtrak passenger train slammed into a tractor-trailer that according to an eyewitness got stuck on the tracks while trying to make a difficult left-hand turn on Monday. One of the train’s cars toppled and the conductor and at least 54 others were injured.

It was the third serious train crash in less than two months. Two deadly crashes in New York and California in February killed a total of seven people and injured 30.

The oversized flatbed trailer involved in Monday’s crash was transporting a modular building wrapped in blue plastic and jammed with electrical equipment, said Lt. Jeff Gordon, a spokesman for the North Carolina State Highway Patrol.

One of the troopers escorting the truck from Clayton, North Carolina to the Virginia border was trying to help the driver negotiate a difficult left-hand turn across the tracks onto a two-lane highway in the town of Halifax, Lt. Gordon said. But the 164-foot tractor-trailer combination couldn’t navigate it, he said.

During the five minutes or so the trooper and driver spent attempting to get the truck turned and off the tracks, there was no indication of an approaching train, Lt. Gordon said. When the train appeared, it set off warning flashers and the crossing arms came down as the truck was still straddling the tracks, he said. The train hit the truck shortly afterward, Lt. Gordon said.

Eyewitness Leslie Cipriani, who was in a car with a friend at a stop sign, heard the sound of the oncoming train and saw the crossing arms hit the tractor-trailer.

“I saw him jump out of the truck when he knew he couldn’t beat it. ...I heard the train noise and thought, ‘Oh, my God, it’s going to happen,’” said Ms. Cipriani, who shot video of the collision with her cellphone.

State transportation officials said 54 of the injured were taken to hospitals with non-life-threatening injuries after Monday’s crash. They said one had more serious injuries. Details were not immediately available.

Among the injured was the train’s conductor, Lt. Gordon said. Federal authorities said they believed 62 people were injured. The discrepancy could not be resolved immediately.

Federal Rail Administration spokesman Michael J. Cole said it appeared that the locomotive and two cars derailed. State transportation officials said one baggage car derailed.

The train had one locomotive and seven cars, Mr. Cole said. He said the authorised speed for the train is 113 kmph, but authorities don’t yet know how fast the train was travelling.

The Amtrak train was the Carolinian, which runs between Charlotte, North Carolina, and New York City daily. It was headed north at the time of the crash.