Introduction to Railroad Signals  and MSS

Railroads have used signals for over 100 years to help trains move safely between locations on the rail that they have laid between various points. They have changed significantly since the early 1900’s where the semaphore type was common to what is in place to day. 

These devices protect trains from running into each other by telling engine crews what is ahead of them on the track. They protect multiple trains on the same track. These systems can become quite complex and the information passed to engine crews is visual in nature. 

Consider the following information on what signal aspect (the colors that are presented to you by the signal heads when you approach the signal) means to a Union Pacific engine crew. By the way...this is one of the simpler ones….

It is beyond the scope of this web site to discuss or describe every signal type, signal aspect and it’s meaning to you but by now you get the idea of what you are up against with signaling on your model railroad. If you want to know more, we recommend you obtain a copy of the 12/15 & 1/16 editions of Railroad Model Craftsman magazine and read Dr. Bruce Chubb’s article “Understanding Railroad Signals” parts 1 & 2.

By now you have probably realized that installing a prototype signal system on your rail road can be an extremely difficult task. The wiring underneath the lay out can get very complicated very quickly. Fortunately for us…there is a new standard that utilizes off the shelf components to install signals that operate prototypically. Let’s now talk about Modular Signal System or MSS. 

The Modular Signal System (MSS) standard. This specification document is a standardized method for animating model railroad signals to react to trains moving along a signaled track without the need for expensive computers or complex software. Having trackside signals automatically change aspects in response to train movement adds significantly to the realism and enjoyment of operating sessions, not to mention enhancing visitors' viewing experience.

MSS simulates basic Absolute Block Signal (ABS) functionality in any model railroad scale and format, though it's especially well-suited for modular model railroads. Any number of signaled tracks can be supported, and any style of trackside signal can be used (e.g. target, tri-light, position-light, semaphores, etc.).

MSS uses low cost CAT5 network cables for interconnections, and can utilize commercially-available model train detectors and signal logic drivers. This gives modelers the flexibility to select components that best fit their budget and specific signaling needs.
For more info on MSS go to the following webs site.