--- In STMFC@..., "armprem1" <armprem@...> wrote:

While this may be marginally within scope of this list,what was the
rule for displaying markers and who determined the colors of the lenses
of marker lights?Was there a standard?Armand Premo

Irregardless of what Tony says, most railroad rulebooks were modeled
on the Standard Code of Operating Rules throughout the period covered
by this list, and so where pretty much the same from road to road. The
biggest noticeable difference was that while most roads used RED
lenses to the rear and GREEN lenses to the sides and front, the PRR
and possibly some other associated roads used YELLOW to the sides and
front. The side that faced the carbody did not have a lens.

Rules for display were pretty standard, also. Keep in mind that nearly
all rulebooks define a "train" as: "Engines or engines coupled with or
without cars, DISPLAYING MARKERS" (emphasis mine). Therefore, a
consist assembled in the yard didn't become a train until the markers
were hung. Likewise, if one was waiting in the clear for a train to
pass and a locomotive and cars went by but no markers, the train
wasn't past. What had gone by might have been the train in the act of
switching, or the front half of a train doubling a hill, but the train
hadn't passed until the markers went by.

Some rulebooks provided for using a red flag on the last car in lieu
of markers during the day. If the last car wasn't equipped with flag
brackets, this was often stuck in the coupler.

Rule 17, the same rule that requires a train standing clear of the
main to dim it's headlight, also required that the rear of a train in
the clear "turn" its markers to display green (or yellow) to the rear.
This was a safety procedure; if a train on the mainline was coming up
on another train and the markers still showed red, it meant the train
wasn't clear. With the old style oil lamps, this was accomplished by
actually swiveling the lamps in their bases so that the red lens faced
the caboose wall.

There were also some variants in this rule that pertained to trains
running the same direction on multiple tracks that I don't remember
well enough to cite.

Dennis