Indiana Code Title 8. Utilities and Transportation § 8-8-1-11

Sec. 11. (a) It is unlawful for a railroad carrier in Indiana that operates freight trains over its lines in the state to maintain over or across its line in this state an overhead bridge, viaduct, or other structure, the lowest point of which is less than twenty-one (21) feet above the level of the top of the rails in the track of the carrier, without obtaining the permission of the Indiana department of transportation so to do.

(b) It is unlawful for a party, person, association, limited liability company, or municipal or private corporation to construct or maintain, across the track of a steam railroad carrier an overhead bridge, viaduct, or other structure the lowest point of which is less than twenty-one (21) feet above the level of the top of the rails in the track without obtaining the permission of the Indiana department of transportation to do so.  This section does not apply to bridges or viaducts within the limits of a city or incorporated town in the state.  This chapter does not modify the statutes concerning the location of wires across railroads, street railroads, interurban, or suburban railroads.  No new structure or new railway bridge shall be built in which the lowest point is less than twenty-two (22) feet above the level of the top of the rails in the track of the carrier, without obtaining permission of the Indiana department of transportation so to do.