Mo. Rev. Stat. § 389.820

From and after the first day of January, 1908, it shall be unlawful for any person, persons, company or corporation, operating any line of railroad, in whole or in part, in this state, either as owner, lessee or receiver, to use or permit to be used or hauled between stations within this state, on said line of railroad, any locomotive, tender, car or other vehicle for moving persons or freight, which shall not be equipped with handholds, grab irons and couplers, coupling automatically by impact, and which can be coupled without the necessity of men going between the ends of the cars for the purpose of effecting such coupling.