Okla. Stat. tit. 40, § 179

It shall be unlawful for any railroad, corporation, or other person, who owns, controls or operates any lines of railroad in the state, to build, construct or repair railroad equipment without first erecting and maintaining at every division point a building or shed over the repair tracks; same to be provided with a floor where such construction or repair is permanently done, so as to provide that all men employed in the construction and repair of cars, trucks, and other railroad equipment, shall be under shelter during snows, sleet, rain, and other inclement weather.