49 C.F.R. § 218.25 Workers on a main track.
Title 49 - Transportation
When workers are on, under, or between rolling equipment on a main track: (a) A blue signal must be displayed at each end of the rolling equipment; and (b) If the rolling equipment to be protected includes one or more locomotives, a blue signal must be attached to the controlling locomotive at a location where it is readily visible to the engineman or operator at the controls of that locomotive. (c) When emergency repair work is to be done on, under, or between a locomotive or one or more cars coupled to a locomotive, and blue signals are not available, the engineman or operator must be notified and effective measures must be taken to protect the workers making the repairs. [44 FR 2175, Jan. 10, 1979, as amended at 48 FR 6123, Feb. 10, 1983]
Title 49: Transportation
PART 218—RAILROAD OPERATING PRACTICES
Subpart B—Blue Signal Protection of Workers
§ 218.25 Workers on a main track.