28. To indicate their presence, a member of each class of employees working on or aboard equipment secured on a track must place, at the ends of that equipment, a blue flag by day, coupled with a blue light at night when the flag is not visible.
Equipment may not be placed on the same track and block a clear view of the signal installed in accordance with the first paragraph, unless the locomotive placing such equipment remains on that track until the signal is relocated to include that equipment with the one to which the signal already applies.
The requirement provided for in the first paragraph does not apply when equipment is placed on a track whose access is prohibited in accordance with subparagraph 1 of the first paragraph of section 56.
The signal provided for in the first paragraph must be set up on staffs at a height that ensures a clear view thereof from the equipment.