Any railroad company owning or operating a railroad or any part thereof in this state, whether chartered under the laws of this state or under the laws of any other state or states, is empowered to relocate or change its lines or tracks, to build second main or double tracks, relocate any part or parts of its lines for the purpose of reducing or taking out curves or reducing grades, and to build embankments for the purpose of avoiding trestles upon which the railroad may be constructed, or to widen cuts when necessary for proper construction; provided, that where there is a relocation of any part of a road and any industry located upon the original road, the railroad shall keep and maintain a spur or sidetrack to such industry; and where any landowner or the heir or devisee or successor in title by conveyance or otherwise of any landowner who donated the original right of way, or who parted with the easement upon or title to the same in any other manner than by voluntary sale for a full cash consideration, shall be injured by such relocation, the railroad company shall be liable therefor; provided, that under this section and §§65-6-118,65-6-123,65-6-129 and65-6-131, no railroad shall be authorized to change the location of its line or lines within any incorporated towns, or cities, except by consent of the governing authorities of such incorporated towns or cities.