I figured I'd start a thread to document my construction techniques for the signals I'm building for my RR. I've always liked signals, but want to integrate them into my operations, both being able to run with and without a dispatcher (since, mostly, Ill be running without).
First, a bit of information. Signals, in their basic form, control entry and exit into a block of track. For purposes of my railroad, these blocks will be the sections between sidings on the line. Prototype railroads have blocks about the length of a train, to allow a much higher density of traffic than simple entry/exit control between sidings.
Anyway, each switch to a siding has to have control both eastbound and westbound. Here's a drawing from the wiki to help explain:
Trains traveling eastbound are controlled by signal R174. Notice that the signal has two heads on it. The upper head controls entry into the straight route, and the lower controls the diverging route. For my RR, I am only using two color signals, so the upper will be R/G, and the lower will be R/Y.
Trains traveling westbound are controlled by signals L174 and LB174. L174 is the signal for when you are on the main, and LB174 is when you are on the siding.
There is various logic to set these signals to their respective aspects (colors) which I will describe later on when I start working on the logic.
But, as we can see, each switch that is on the mainline of my RR will need three signals, one two-head, and two single-head.