Mo. Rev. Stat. § 151.130
In any case where a railroad is built along any county line, or where the line dividing any two or more counties is crossed and recrossed by any such railroad, in order to ascertain the exact amount of railroad bed and track which belongs within the lines of each of the respective counties, the county commissions of each of such counties are hereby authorized and required to cause a survey of the same to be made, and it shall be the duty of the county commissions to appoint the county surveyor, or some other suitable person, for each of their respective counties, who shall proceed jointly to survey, locate and establish such line; and such surveyor shall commence at the first intersection of the county line with such railroad, at either end of the same, as it may suit their convenience, and make a correct survey of the same, and measure correctly all portions of the bed and track of such railroad which they find on either side of such county line. They shall file in the office of the county clerk of each of their respective counties a correct plat of such survey, with the notes of the same, showing the exact amount of roadbed which belongs within the lines of each of the respective counties; and in all cases hereafter, in the assessment and collection of the revenue on such railroads, the county commission shall be governed by such survey.
§ 151.130, RSMo
Effective 6/20/1986