Mo. Rev. Stat. § 429.440
All persons who shall do any work or labor in constructing or improving the roadbed, rolling stock, station houses, depots, bridges or culverts of any railroad company, incorporated under the laws of this state, or owning or operating a railroad within this state, and all persons who shall furnish ties, fuel, bridges or material to such railroad company, shall have for the work done and labor performed, and for the materials furnished, a lien upon the roadbed, station houses, depots, bridges, rolling stock, real estate and improvements of such railroad, upon complying with the provisions herein mentioned; provided, such work and labor is performed, and such materials are furnished, under and in pursuance of a contract with such railroad company, its agents, contractors, subcontractors, lessees, trustees, or construction company, organized for the uses and purposes of such railroad company, or having in charge the building, construction or improvement of such railroad, or any part thereof.
§ 429.440, RSMo