Union Pacific spokesman Mark Davis told the Associated Press that one of its coal trains collided with another train carrying cargo about 6.50am local time Thursday near Grand Junction, Iowa, about 60 miles from Des Moines.

Both derailed. The UP train lost seven coal-filled cars while the intermodal train lost 13.

Investigators are still looking at the cause of the incident, but a fire official told local news station KCCI that a malfunction may have prevented the container train from moving to another track.

All traffic was still halted Thursday afternoon on the line between Chicago and UP’s Iowa and Nebraska destinations. Plans are being made for reroutes if the tracks are not soon cleared.

On Wednesday night in Illinois, a Burlington Northern Santa Fe train left the tracks in Pekin, near Peoria.

According to WMBD, one of the cars split open and spilled coal onto the tracks.

No information was released on the route the train was taking or how many cars derailed.

Investigators are looking into the incident.