Thirty-four cars of a Union Pacific Railroad coal train have derailed in northeast Colorado.

Railroad spokesman Mark Davis said no injuries were reported after the eastbound train cars went off the track around 2:40 p.m. Thursday, about eight miles west of Limon. It's unknown why the cars derailed.

Davis said crews would work through the night to remove derailed cars and repair the track. He said the line may reopen Friday.

It wasn't immediately known where the train originated.

The line where the accident happened carries traffic from Denver to Kansas City. Davis said a detour is available through Cheyenne, Wyo., and Nebraska.