If a county, in the exercise of a power granted by this subchapter, including the power of eminent domain or the power of relocation, makes necessary the relocation, rerouting, or alteration of the construction of a highway, railroad, electric transmission line, pipeline, or telephone or telegraph property or facility, the relocation, rerouting, or alteration of construction must be accomplished at the sole expense of the county. In this section, "sole expense" means the actual cost of the relocation, rerouting, or alteration of construction to provide comparable replacement without enhancement of the facility, after deduction of the net salvage value derived from the old facility.
Tex. Gov't. Code § 1477.072