Lower quadrant semaphores
The train order signals I'm using have two semaphore blades
and illuminated red, yellow, and green aspects. These are lower
quadrant semaphores. That means that when a blade is fully
down (the vertical position) it is displaying the green aspect.
When the blade is fully raised (the horizontal position) it is dis-
playing a red aspect. When the blade is at a 45
o
angle pointing
down it is displaying a yellow aspect.
A red train order signal tells a train crew that Form 31 train
order(s) are waiting and they must stop and sign for receipt of
the new orders before they proceeding. A yellow aspect tells
a train crew that Form 19 train order(s) are waiting and they
should expect to find the operator out on the station platform,
ready to "hoop up" the orders to them as they pass. Needless
to say, crews preferred Form 19 orders so they could grab 'em
without stopping.
Up the Creek Column - 6
red aspect
green aspect
yellow aspect
MRH-Oct 2013
