Union Pacific rail crews were investigating the cause of an 18-car derailment Monday morning near Tennessee Road in Texarkana, Ark.

The 79-car freight train was traveling from Pine Bluff, Ark., to Eagle Pass, Texas, when it derailed about 5:40 a.m. Monday in southeastern Texarkana, said James Barnes, director of media information for Union Pacific.

No one was hurt.

The freight train was carrying empty auto racks, lumber, clay, soybean oil, steel bars and railroad ties.

The derailment occurred on the single main line; trains are being rerouted...