Routing for your trains

Routing systems for a layout makes operation much more straightforward and less easy to set thing wrong. If you have noticed, in a real mechanical interlocking signal box, the signalman requires considerable skill and experience to route the trains safely through his domain.

With the arrival of electro mechanical interlocking and before computers, the task became a bit more intuitive. One common system used was referred to as an NX (entrance exit) panel. Here you press switches along the route you wish the train to go. If the route is free of conflicts, the route and the appropriate signals will be set and locked until the passage of the train or the routing is cancelled. This is possible on a model railway but requires rather a lot of complicated wiring and many relay interlocking circuits.

There is a much simpler way of achieving a routing system for model railways as long as you are willing to accept the absence of any form of interlocking and inter linked automatic signalling systems. Non-locking push-to-make switches can be located where routes divide or merge, and on operation of the correct switch a group of point can be set in the appropriate position. There is no generic format for this, each layout has to be custom designed for the track layout. A ilmitation is the power of the capacitor discharge unit, but the correct type can be made to operate up to six or more Peco-type point motors simultaneously. Using common return from the point motors reduces the amount of wiring considerably.

To understand this routing system, a wiring diagram absolutely essential. Draw all your point motors showing the set and reset connections. Plan where the routing switches are to be located and installed in geographic position on the control panel. One side of all the routing switches is connected to the positive of the capacitor discharge unit. The common of all the point motors is connected to the negative of the capacitor discharge unit.

Stacks Image 1039
Now comes the fun bit.

Starting with the first route, on the diagram draw the wire to the points you wish to set or reset. Do this for all routes until you come to a point motor with a wire already on the terminal you wish to connect to. In this situation two diodes are required at the point motor to prevent feedback to other routes. If you follow the logic of the routed wires it does make sense.


Stacks Image 4416
Alternatively if you have for example four routes converging into one, it is possible to wire the point motors in series as long as the capacitor discharge unit has adequate power. No diodes are required in this situation.