Nobody was injured and no damage occurred when the wheels of eight cars for a CSX train were "slightly off the rail" early Thursday morning, a company spokesman said.
Spokesman Gary Sease, who is based at the company's headquarters in Jacksonville, Fla., said the cars were upright, in line and parallel to the tracks.
The incident occurred as workers were pushing cars over what Sease called the "classification hump," or processing cars and routing them to connect to a train.
Sease said company officials are looking into a cause -- a process that could take several days, he said.
He was asked if the company suspects anything suspicious.
"Until we've got a cause, we don't really speculate," he said. "We've got a very good record of preventing derailments. It's measured per million train miles."
He added CSX was named the safest railroad in 2013.
Sease said the incident interfered with the ability to operate the yard until workers could re-rail the cars. That was completed by mid-afternoon, Sease said.
Ohio 13, between U.S. 224 and U.S. 250 in Huron County, was closed Thursday morning as a result of the incident. By 8:30 a.m., the road was re-opened because the train that had been blocking the tracks was separated, allowing traffic to pass through the area.
"Once we determined there wasn't any immediate hazard to anybody, we were done," Willard City Manager Brian Humphress said about the city's involvement.