Tenn. Code § 65-11-111
Each railroad company owning or operating the track or tracks at any grade crossing ordered or agreed to be eliminated under this chapter shall bear fifty percent (50%) of the total cost of the elimination of any such grade crossing, the total cost to include the cost of the construction of the underpass or overpass substituted for the grade crossing, of the approaches thereto, of the surveys and preparations of the plans and estimates of cost for such underpass or overpass crossing ordered by the commissioner of transportation or the commissioner's designee, and of any revision of the grade and layout of the railroad tracks directly made necessary by such grade separation, but shall not include the cost of metal surfacing or road pavement required in accomplishing the elimination of any grade crossing; provided, that any disagreement between the commissioner or the commissioner's designee and the railroad company affected with regard to the extent or cost of any such revision of the grade and layout of the railroad tracks directly made necessary by any grade separation, shall be resolved by the commissioner, and the commissioner's decision shall be final. The remaining fifty percent (50%) of the total cost shall be borne out of the public funds as a part of the cost of the highway of which the crossing is a part; provided, that a detailed statement of the expense of all that part of the construction of such underpass or overpass crossing, including the preparation of the detailed plans and specifications, etc., which is conducted by the railroad company, shall be submitted to the commissioner or the commissioner's designee, duly sworn to by some official of the railroad company, having knowledge of the facts; and provided, further, that this provision for the division of cost between the public and the railroad company shall apply only to crossings already in existence or hereafter made, or proposed over railroad tracks in existence at the date of the order for elimination thereof, and shall not apply to any crossing of any highway by any railroad track not in existence at the date of the designation of such highway as a part of the state highway system by the department of transportation.
T.C.A. § 65-11-111