signalling light placement

[dehusman]

Assuming you want to model CTC (centralized traffic control) signals, the signals will be placed to control movement over a switch or group of switches. lets say you have a siding. At the switch at the right end of the siding you have three ways to get over the switch:
1 - from the siding (moving to the right)
2 - from the main (moving to the right)
3 - from the main (moving to the left)
You would have one signal for each of these routes. The signals would face out, away from the switch.
At a crossover you would have 4 ways into the switches 1 for each track approaching from the left and one for each track approaching from the right. You would have 4 signals, two on the left side of the crossover, two on the right side of the crossover. One for each track on each side, all facing away from the crossover towards and approaching train.
At a crossing you would have one signal on either side of the crossing for each track. Once again all the signals would face away from the crossing. So if you had a single track crossing a single track you would have 4 signals, If you had double track crossing single track you would have 6 signals.

If you have long distances (over a train length) between control points (switches) then you will have "intermediate" signals, a pair (one facing in either direction) for each track.

Normally signals are placed to the right of the track in the direction of movement. So if the track runs east-west, and eastbound train will find the signals on the south (righthand) side of the track. On double track, the signals will be to the outside. So an eastbound train on the south track will have the signals on the left and and eastbound train on the north track will have the signals on the left side. On multiple tracks the signals may be placed on a signal bridge over the tracks they control.

At switches, the signals are placed at the clearance points around the switch. If a track runs east-west and there is a siding, at the east end of the siding there will be a signal on the north side of the tracks facing east governing westbound movements toward the switch, there will be a signal on the north side of the siding at the clearance point (where the siding becomes parallel to the main track) facing west governing eastbound movements from the siding to the switch and there will be a signal on the south side of the main track lined up with the signal on the siding facing west governing eastbound movements over the switch.

Hope this helps.

Dave H.

[Anonymous]

We're working on our first layout (nscale-kato) and wanted to use some of their signalling tracks... it changed red/green/yellow after a train has gone across it.

Anyway, where would one normally place these in a layout? Which "direction" would they want to be facing, based on where they are placed?

TIA.