Cleanup continued early Monday at the site of a train derailment in northeast Louisiana.

The engineer and conductor were injured when a freight train hit a truck Sunday at a crossing in Mer Rouge, derailing two engines and 17 cars of the 87-car train, state police said.

Crews worked throughout the night and could have line open later Monday, troopers said.

Union Pacific Railroad Co. officials said the conductor's injuries weren't considered life-threatening. He was being treated at a hospital in Shreveport. They say the engineer suffered minor injuries.

Mer Rouge Police Chief Mitch Stephens said about 50 houses were evacuated for about two hours due to concerns that a tank car of pressurized argon gas might explode. Another tank of argon, an inert gas used to fill light bulbs and in arc welding, leaked until it was empty, he said.

Stephens said the trailer got stuck on the tracks crossing Highway 165, but trucker Daniel Shackleford, of Freedom, Missouri, was unhurt. Shackleford was hauling a rig owned by Taylor Truck Line of Northfield, Minnesota.

"He saw the train coming and he jumped out of the truck," Stephens said.