Model Railroad Signals

Model Railroad Signals

By Roger Heid

 

Somewhere along the line you have decided to add some signals to your layout. There has been some confusion as to how to go about this.

Different types of signals are available from several manufacturers. Ulrich Albrecht has published a blog dealing with railroad signals used in the real world, explaining what they are for and what they do. I try to look at this scenario from the model railroader’s point of view to give you an idea what you are dealing with in the model railroad environment.

There are two basic types of signals, those featuring semaphore arms and discs, and those utilizing lights instead. The up tilted semaphore arms or discs are equivalent to a green light on a road traffic stop light.

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Samples of Model Railroad Signals

Initially, there are two ways to add one or more signals to your layout. You can just simply install them just for the show, to add some visual pizzazz to your layout. Then you can operate them via remote control to make the semaphore arm move up and down and/or change the lights on light signals. You would have to power them up and use either a switch box or an appropriate decoder to get that accomplished.

If a given signal happens to be set in the ‘Stop’ mode it is up to the loco operator to obey the signal or to ignore it, in which case the ‘Model Railroad Police’ will bless you with a ‘Model Ticket’. Shame on you! The choice is up to you.

Above and beyond that, a model signal, just by itself, will not do anything else. It will not affect the train’s behavior at all. If you want the status of the signal actually affect the train’s motion you will have to install additional hardware. That’s when things become tedious for a beginner.

In an analog environment, there is a way to do this. You can wire the switch box in such a way that it also turns a relay on and off which in turn shuts the track power on an isolated stretch of tracks off and on. When a signal is set in the ‘Stop’ mode it will also turn the track power off. Once the signal is changed into the ‘Go’ mode, the track power comes alive and the train can move again. This is one way to do this.

In a digitally automated layout, things will become rather complicated. Here you will have to install sensor equipment and decoders. These sensors will sense the presence of a train/loco on a given spot along the tracks. These sensors can be a function track section, a reed switch or an infrared motion detector device, for instance. A reed switch is a small device that responds to the presence of a magnet. Take note that a reed switch will not work reliably with Maerklin M track as the road bed body is made of magnetic metal. A sensor will give a signal to a decoder which, in turn, will activate whatever you intend and program it to do.

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Maerklin Contact Tracks

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Reed Switch

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Samples of Infrared Motion Detectors

This blog is intended to be a guideline for beginners. I will therefore refrain from pushing more technical details for advanced layouts. These details will have to be dealt with on a case to case basis. My advice is that a beginner does not indulge in sophisticated signal operation. First get the trains running. Remember, Rome was not built in one day.

Please, post all questions in the Forum under the topic ‘Technical Corner’. The Blog System is not designed to answer questions.

Thank you.

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