(a) In this section, "sole expense" means the actual cost of relocating, raising, lowering, rerouting, changing the grade of, or altering the construction of a facility described by Subsection (b) to provide comparable replacement without enhancement of the facility, after deducting from that cost the net salvage value derived from the old facility.
(b) If the authority's exercise of the power of eminent domain makes necessary relocating, raising, lowering, rerouting, changing the grade of, or altering the construction of a highway, railroad, electric transmission or distribution line, telephone or telegraph property or facility, or pipeline, the necessary action shall be accomplished at the sole expense of the authority.