GRAND JUNCTION, Iowa (AP) -- Crews repairing a train derailment in central Iowa have reopened one of two affected tracks.

Union Pacific spokesman Mark Davis says the track was reopened at 11 a.m. Friday and trains are operating on it. The other track is expected to open Friday afternoon.

Davis says an eastbound coal train on its way from Wyoming to Crescent, Ill., derailed Thursday morning into a westbound cargo train going from Chicago to Oakland, Calif. The impact derailed 13 of the 135 cars on the coal train and 22 of the 106 cars of the intermodal cargo train.

Davis says a team is investigating what caused the derailment. The crash shut down a section of the company's mainline tracks near Grand Junction about 60 miles northwest of Des Moines. No injuries were reported.