DENISON, Iowa (AP) — Railroads crews are cleaning up after 22 cars of a coal train derailed in western Iowa.

Mark Davis, spokesman for Omaha, Neb.-based Union Pacific, says the 136-car train was headed from Wyoming to Illinois when a section derailed about 6:40 a.m. Sunday. No injuries were reported.

Davis says crews will work into Monday to clear debris and repair about 800 feet of damaged track that stretches over two rail lines. One of the lines is expected to reopen early Monday.

The cause of the derailment is under investigation.