I like the PRR Semaphore era, but it may be a bit confusing, as I am too confused as to why a one, two, or 3 bladed semaphore was needed at any particular interlocking, or block ... as all signal bridges had totally different arrangements, on track 1, track 2, track 3, and track 4
When the early "Tombstone" Position Light Signal came about, having 4 lights per aspect (costing 1/4th more in bulb and wiring costs) the signals became even more complex to read
Then came the Position Light Signal (PLS), and on track 1, track 2, track 3, and track 4 all types of different signal arrangements were used on each track. Track one might have had a top round backboard with 4 different aspects, and having a bottom round backboard that had chopped off sides, only showing 3 different aspects (no horizontal lights) ... then there were the no backboard signals that either had a R to L, or a L to R diagonal strip of thin metal with lights attached to the crossbars ... then there were the bottom backboards that were straight up and down ... while others had only a single bottom light
Surely the various complex signal arrangements were very confusing, especially at speed !
Then came the much easier to read Color Position Light (CPL) which I am not a fan of (but I do agree that for safety purposes they were the best
I need to know how to read these signals, and find out why on track 1, track 2, track 3, and track 4 they were always somewhat different configuration ?
I always thought that a bottom signal board meant the next nearest block aspect ... and the top board showing the next thereafter distant block aspect
I am modeling the very early yellow PLS signals, just after the demise of the Tombstone era signals, where just about every switch had a kerosene lantern or Red/Green, or Blue/Yellow