- The purpose of this article is to guide you in deciding how to use signals on your model railroad, as part of a control system plan. I recommend you study the article on control systems in this primer first. It provides the overall scheme that includes signals.
- WARNING - Signalling for model railroads is an area where study and modeling of the real thing can become a hobby in itself.
II. SIGNAL CLASSES BY FUNCTION
- Signals can be DECORATIVE, PASSIVE,or ACTIVE.
- Decorative signals provide no useful information, and are simply another piece of scenery. Study the prototype, and buy, build, and place as appropriate.
- Passive signals
- Passive signals have the purpose of providing some control information to a RR crew member. They may or may not be lighted, but they never change. By their nature, passive signals would be located along the track. They hopefully will also be decorative.
- Possible information provided by passive signals:
- Location of the end/start of a block
- Location of an electrical gap
- Location of the end of a zone of control
- Location of a clearance point. (The other train can get by without hitting your train)
- Location for applying the ASPECT (appearance, like red over green) and INDICATION (meaning, like STOP) of an active signal display located somewhere else
- Active Signals
- Active signals change. They can move or change color, or turn on and off. As with passive signals, it is nice if you can make them decorative, BUT, the function of active signals is to present changing control information to the operators.
- Active signals can be operated manually, or be partially or completely automatic.
- Possible information provided by active signals:
- All of the above listed for passive signals.
- Route to be taken beyond that signal
- Whether or not to proceed past the signal, and at what speed.
- Any other agreed-upon simple message arranged as part of the operating rules for a real or model RR. (For example, stop to recieve orders at the station)
III. SELECTIVE COMPRESSION OF SIGNALS
- Safety requirements, lawyers, and the laws of physics often forced railroads to build very complicated signalling systems. You may enjoy modelling these precisely, but a model RR can operate very smoothly with simplified signals. Active signals in particular should be just complicated enough to do the job of giving the operators the information they need to do their jobs.
IV. OBTAINING YOUR SIGNALS
- Several manufacturers will be glad to sell you their plastic or metal models of signals. Models of active signals tend to be expensive.
- If you want a lot of active signals on your railroad, consider making your own. Most signals are made of basic shapes, and brass rod, tube, wire, sheet, and simple brass or plastic detail parts solder or glue up easily into signals.
- Today, light-emitting diodes do the best job of lighting signals. They come in a variety of sizes and shapes, and red/green and red/yellow/green color combinations are easy to achieve.
- The signals which use mechanical position, like semaphores, give a real sense of railroad history to a model railroad. No free lunch, though: expect to spend a lot more time and $ if you choose this route.
V. REFERENCES - Appendix A
- Please refer to the references list in my companion article on control systems
- Please E-mail me at my address shown above if you have suggestions to make on commonly available references specicifically relating to signals.
VI. LIST OF VENDORS - Appendix B
I hope that this article helps you to get a start on using passive or active signals on your model RR.
David Gibbons - Copyright 1996