Tennessee Code Title 65. Public Utilities and Carriers § 65-6-201

(a) The minimum clearance requirements for all railroads operating in this state, in the construction or relocation subsequent to April 13, 1949, of tracks, tunnels, bridges, or structures adjacent to tracks, shall be as described in this part, except as otherwise provided.

(b) No railroad corporation shall operate any cars, trains, motors, engines, or other rolling equipment on its tracks, or tracks of others, except as provided in this part, on which overhead or side clearances, or clearances between tracks, are less than the minimum prescribed in this part, if such tracks, bridges, tunnels or structures adjacent to such track are constructed or relocated subsequent to April 13, 1949.