I need some help visualizing how to install signals at a simple junction where two tracks become one. It is where a long passing siding rejoins the main. Should there be two signal heads on a mast to the right side of the tracks - the siding being on the right. Or would a single head provide enough info to control traffic on both tracks? And what aspects would you recommend for the switch positions? The layout is mostly early 1950’s Pennsy, but the tracks are shared also by Erie, NYC and NKP. I am not bound to PRR position lights, but I do like 'em. My plan is to wire them to Tortoise switch machine inputs, so there is no need for detection circuits and the like. I just need to indicate the switch position in a fairly prototypical manner.
The key is what type of signal system are you installing?
Is is CTC, where the dispatcher controls the switch and the signals and the signals grant authority to occupy the track or is it ABS/APB where the trains use train orders or track warrants (or other methods) to have authority to use the main track and the signal system indicates track occupancy?
If its CTC then you need 3 signals, all facing away from the switch. On on the single track approaching the switch, one on the main (between the siding switches) and one on the siding.
If its ABS/APB then all you need is two signals, both on the single main track beyond the switch, one facing in each direction.
The other alternative is you aren’t actually using them as a real signal system, you just want them to indicate which way the switch is thrown. In that case use the arrangement with CTC and put 2 heads on the one on the single track. When the switch is lined for the main track, the signal on the siding would be red, the signal on the main beside the siding would green and the signal on the single track would be green over red. When the switch is lined for the siding the signal on the siding would be green, the signal on the main beside the siding would be red and the signal on the single track would be red over green.
Dave H.
Have you looked into the Signal Animator by Logic Rail?this is a simple effective way for sigaling using a time delay for yellow.
Hi bear with me on this
As you aproach the frog end of the points you will have two signals one for each line the side of the line they are on will depend on the prototype practice in that area. I am used to the left so will use that.
Aproaching the points in the facing direction IE the toes of the blades you will have a two head signal on the left the highest one will be for the main line, the lowest one for the passing loop or siding
There may also be a low speed shunt light a signal only capable of exibiting a yellow light or no light this one is only there if operations dictate a need for it.
I would if you can set it so your signal shows the correct aspects IE red if it cannot proceed because the points are the wrong way the green for the line where the train can proceed.
I have no idea how to do it but I would want the two opposing signals to show correctly green for the train to proceed and the opposing signal red not signald for a head on smash.
Which would mean resorting to some sort of electrical interlocking which is beyond me.
regards John Busby