Tex. Gov't Code § 1477.121

If a county, in the exercise of a power under this subchapter, including the power of eminent domain or the power of relocation, makes necessary the relocation or rerouting of, or alteration of the construction of, a highway, railroad, electric transmission line or pipeline, or telegraph or telephone property or facility, the relocation or rerouting or alteration of construction must be accomplished at the sole expense of the county.