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3 and 4 aspect signalling


We have a range of boards which make multi aspect colour light signals change in the correct way with the passage of trains. These boards are very flexible in use and simple to wire. Installations can range from a single signal to complex junctions with route indicators (feathers). If you need more information about how full size signals work and to compare their operation with our units see our signalling page. This page provides an overview of all the compatible units for 3 and 4 aspect signalling with links to pages explaining the operation of each unit. The boards work with both DC and DCC as our signal control boards have no connections to the track.

Each unit has one or more infra red detectors built into it. This allows the units to know when a train is passing the signal. One unit is required for every signal. Each unit is positioned past the signal it controls. When a train reaches the unit the train is detected by the units infra red and the signal changes to red.


This allows a single 2 3 or 4 aspect signal to be operated on its own. Unlike the IRDASC units the MAS Sequencer works with a built in timer. Once the train has cleared the MAS Sequencer the timing starts. It is a very simple method of controlling a single signal on a line but with a link wire to one or more IRDASC units it can form the last control of a line of signals which change colour in the correct sequence.

The diagram shows the simplicity of the wiring. Link to MAS Sequencer


If you have 2 or more signals along the same stretch of line then the last signal reached is controlled by a MAS Sequencer. IRDASC-4s control each signal leading up to the MAS Sequencer controlled signal. They set their aspect according to the signal ahead. The video at the beginning of this page shows 2 signals controlled by a MAS Sequencer and an IRDASC-4. Link to IRDASC-4. If a complete oval is signalled then all IRDASC-4s with no MAS Sequencer can be used.


This board works in the same way as the IRDASC-4 but in addition it switches the power off to the track whilst the sigal is at red. By having a short section of isolated track in front of the signal this allows a number of trains to run on the same oval without catching each other up or colliding.

Link to IRDASC-5.


This functions exactly as rhe IRDASC-4 but has additional controls to operate a feather (route indicator). Link to IRDASC-4RI


This has additional controls to operate a feather (route indicator) and to isolate the track when the signal is at red. Link to IRDASC-5RI


This works as the MAS Sequencer with the addition of controls to operate a feather. It allows either a single junction signal to be controlled or for a junction signal to be controlled at the end of a chain of IRDASC-4 controlled signals. For situations where the signal is very close to the point we have the MAS-Sequencer-RI2EW. This has two sets of extended leads Link to MAS Sequencer-RI


All these units can be combined together to signal complex junctions in a straightforward way but they can also be used very simply to control a single signal and anything between the two.