KB408: Introduction to the Digitrax SE8C Signaling

This article was last updated on Sept. 18, 2011, 4:56 p.m. | Print Article | Leave Feedback

Security Elements

The Digitrax Signaling System is organized around the concept of what we call "security elements", which are similar to what U.S. prototype railroads call "plants" or "interlockings".


The Digitrax SE8C signal decoder displays aspects for up to 32 heads for 8 individual security elements (plants) using either a LocoNet Throttle or a computer with compatible software.

When used with associated occupancy detectors and compatible software, the SE8C can be set up to protect the turnout with signals as shown by the example below.

Note that trains can move from A to B, A to C, B to A or C to A, but they cannot directly move between B and C.

Going from B to C requires first going to A.


The SE8C decodes switch commands from a throttle or associated software so that the appropriate aspects are displayed on the signal heads.

Each security element is made up of three legs designated A, B, & C.

Every piece of track on your layout can be broken down into security elements to describe how each detection section connects to the other sections on your layout.

Occupancy detection is required for the Digitrax Signaling System to function.


Occupancy detection inputs can be handled by any LocoNet compatible occupancy detector (Either BDL16-Series Occupancy Detectors or BD4 Occupancy Detectors will work).

Transponding is NOT needed for the Digitrax Signaling System.


The SE8C sends its output to the signal driver connections (DRV1 - DRV8) to drive the signal heads.

Each SE8C has 8 sets of signal drivers, each capable of driving a set of signal masts.

Each set of masts can have up to four heads and each head can have up to four different lamps or a multi-color searchlight. The heads may be on separate single masts, dual masts, or gantries. Each mast has its own signal driver connection.

In practice, each set of signal masts usually corresponds to the track controlled by a single security element. Each SE8C signal decoder and occupancy detector is connected to LocoNet so that all security elements on the layout can communicate with each other as the occupancy of each detection section of track changes.

Since the Digitrax Signal System communicates through LocoNet, it does not need DCC to work. The SE8C signal decoders and BDL16 Series occupancy detectors can communicate directly with other LocoNet devices on the layout, they do not need a command station for this communication. This means that they can be used on non LocoNet DCC systems and DC systems where LocoNet is added to support signaling.

The SE8C lets you control of signals manually from your Digitrax throttles or automatically through LocoNet compatible computer software such as Railroad & Company and others.

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