Mo. Rev. Stat. § 91.780
The term "rapid transit improvement", as used in sections 91.780 to 91.840, shall include every improvement for local public use in connection with the transportation or movements of persons and, or property, so designed as to eliminate interference with or by ordinary travel upon the public highways and in public places, and located upon, over, above, below, across, through or along any street, avenue, road, highway, bridge, viaduct, public place, or private property within or without the municipal corporate limits, including all subways, tunnels, elevated highways and structures, walks, bridges, viaducts, surface construction, approaches, loops, stations, entrances, exits, yards, buildings, lands, rights-of-way or other easements, estates or interests of land, which may be necessary, convenient or expedient for the proper construction, equipment, maintenance or use of such rapid transit improvement. Such rapid transit improvement, when municipally owned or controlled, shall be deemed to be a public work and a local improvement.
§ 91.780, RSMo