Mo. Rev. Stat. § 389.996

The division may investigate the cause of all accidents on any railroad or street railroad within this state which result in loss of life or injury to persons or property. Every railroad corporation and street railroad corporation is hereby required to give immediate notice to the division of every accident happening upon any line of railroad or street railroad owned, operated, controlled or leased by it, within this state in such manner as the division may direct. Such notice shall not be admitted as evidence or used for any purpose against such railroad corporation or street railroad corporation giving such notice in any suit or action for damages growing out of any matter mentioned in such notice.