Mo. Rev. Stat. § 388.350
Any railroad company organized under the laws of this state, or under the laws of any other state, a portion of whose line of railroad is constructed within this state, shall have the right to build extensions and branches of its line of railroad within this state of such length and in such direction as may be authorized by resolution adopted by its board of directors at any regular or special meeting of said board, which resolution shall show the county or counties into or through which said extension or branch railroad shall be constructed, and shall set forth the length of said extension or branch railroad and the proposed cost thereof and the intention of said railroad company to build the same. A certified copy of such resolution of the board of directors shall be filed in the office of the secretary of state, and when so filed shall be held and deemed to be an amendment to the charter of said corporation; provided, that before any railroad company shall extend its line or branches under the provisions of sections 388.350 to 388.370, it shall pay the same fees to the state as is now or may hereafter be provided for an original charter.
§ 388.350, RSMo
RSMo 1939 § 5151