A train jumped the tracks near downtown Lytle on Friday morning, the Atascosa County Sheriff's Office reported.
Union Pacific could not say how many of the cars were off the tracks after the derailment around 8 a.m.
The Lytle Police Department confirmed that the train was pulling empty propane tank containers and was not hauling any hazardous materials.
A Union Pacific spokesman said the area wad secured and there was no danger to the community.
No injuries were reported, and Union Pacific had workers on the scene to clear the area about an hour after the derailment.