Saturday 23 March 2024

NEAG March 2024 meeting

Around 14 members gathered for a slightly early "April" meeting, for group organiser Andrew's demonstration of how he is working the colour-light signals on his Swinton layout.

Andrew had knocked up a demo board using Kato N gauge track, with various wiring and electronics that he patiently explained, with the help of the computer and a whiteboard. We were treated to a cab view video travelling through the real Swinton, and even had the added benefit of direct experience: one of our members (Ed) works through the station regularly, and shared his frustration with the signalman who has been known to wrongly set the route for Doncaster rather than Leeds after changes to the timetable... The only teething problem today was in the practical demonstration when it transpired that Andrew had unplugged a key component in order to pass it around the group for closer inspection, but no-one had thought to plug it back in again.

The signals themselves are from Absolute Aspects, who were happy to supply only the heads (and feather route indicators), given that Andrew wants, naturally, to scratchbuild more prototypical posts. The main thrust of the talk was how he is using Arduino boards to control the logic for operating the signals: the board is fed information both about the setting of the points – because this is a junction – and about the track occupancy – so that the signals go red automatically as trains pass through them. Occupancy detection uses a nifty little board from Megapoints:

This is just wired in series to the track power feed, and uses an optocoupler to isolate the wires to the Arduino. By programming the Arduino, it is then quite straightforward to get the signals not only to deal with the necessary logic, but also to cycle through the sequence of aspects based on a timer, to pretend that the train is heading on up the line when in reality it's just entered the fiddle yard. We were suitably impressed!

Oh, and of course we were treated to the usual delicious tea...

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