In case any such railroad or railway, is or shall be located in part on private right-of-way, the owner thereof shall have the right to construct and operate the same across any county road or county street which intersects such private right-of-way, if such crossing is so constructed and maintained as to do no unnecessary damage: PROVIDED, That any person or corporation constructing such crossing or operating such railroad or railway on or along such county road or public street shall be liable to the county for all necessary expense incurred in restoring such county road or public street to a suitable condition for travel.