Michigan Administrative Code
Department - Labor and Economic Opportunity
MIOSHA
General Industry and Construction Safety and Occupational Health Standards
General Industry Safety Standards
Part 1 - General Provisions
Section R. 408.10026 - De-railers, bumper blocks, and clearance signs

(1) Where rolling railroad cars on a spur track could make contact with a railcar being loaded or unloaded, repaired or serviced, or enter a building, work or traffic area, de-railers, bumper blocks, a blue flag or blue light, or other equivalent protection shall be used.

(2) A visible "Close Clearance" sign shall be used to indicate close clearance between a railcar and an adjacent fixed object if the fixed object is located less than 8 1/2 feet from the center of a straight track and 9 feet from the center of a curved track.