Understanding Railroad Signals Part 3


CRAFTSMAN/Dr. Bruce Chubb, MMR, photos by the author


Adding Signals to your railroad allows the movement of trains to be coordinated by a dispatcher. Crews quickly learn how to read the signals and receive their “orders” from them. Signaling really creates a more enjoyable model railroading experience for those running the railroad while adding an interesting animated sce- nic element to the layout as well.


Speed Signaling Versus Route Signaling


Fundamentally, there are two


different schools of thought regard- ing how prototype signal aspects should be used and interpreted for controlling train movements through interlocking controlled turnouts, i.e., an interlocking plant. The first, called “Speed Sig- naling,” uses aspects to define the specific maximum speed that a train may travel through an inter- locking plant. The second, called “Route Signaling,” simply uses as- pects to define that a train is set up


54 RAILROAD MODEL CRAFTSMAN


to take a diverging route through the interlocking plant. With route signaling, it is up to the train crew — using means other than the sig- nal aspect — to know the correct prescribed speed for taking the di- verging route. For example, with route signaling, train speed for taking the diverging route through each interlocking plant could be posted in the employee timetable or in special instruction books. Speed signaling has the advan-


tage that the prescribed speed is defined directly by the signal as- pect itself. However, implement-


ing speed signaling, because of the many additional required sig- nal aspects, is much more com- plex and costly. This is true on the prototype, and these factors tend to carry over to modeling. On the other hand, route signaling — with its reduced number of required as- pects — is easier and less costly to implement both on the prototype and on the model (See Figure 1 for Speed Signaling Application Ex- amples, page 56). Speed signaling, with its tradi-


tional implementation, is normally used by Eastern railroads. Speed


Understanding Railroad Signals - Part 3


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