TRAIN DETECTION ON HELM’S DEEP MODEL RAILWAY

Train Detection On Helm’s Deep Model Railway.
Train detection has been achieved using the principle of track circuits (the track circuit block working system) as predominately employed on the railways in the UK, and throughout the world too.
Railway lines are divided up into individual block sections, once these block sections become occupied some form of indication is fed back to the controlling signal box or signalling control centre.
Furthermore, the signalling interlocking which is in addition controlled by the status of individual track circuits either being detected as unoccupied or occupied controls the status of line-side fixed signals which in themselves display either danger (red) or proceed (yellow, two-yellows, or Green depending upon the set-up of the signalling employed)
A further safeguard is employed wherever points (switches) or crossings are employed, once a track circuit through points and crossings become occupied, it is no longer possible to move these points from one position to another until the controlling track circuit once again detects unoccupied.
As can be seen on this video, I’ve divided Helm’s Deep model railway into ‘block sections’, commonly referred to as ‘signal sections’ utilising individual track circuits.
These track circuits control the status of the signalling and also lock points (switches) into position (once occupied)
I’ve achieved this via the use of infrared detectors placed beneath the layout and pointing upwards vertically between individual sleepers.
These detectors are placed at each extremity to each individual track circuit, there are 32 track circuits in total on the layout, controlled by in excess of 80 or so infrared detectors.
These infrared detectors are in turn connected to 2 miniature relay interlockings, situated beneath the layout, some 600 double-pole double-throw 12 volt relays are employed.
The infrared detectors see anything passing above them and anything stationary above them too.
Once the object above (train, locomotive, wagons, coaches, anything at all) passes clear, there is a 4 second delay timer built into the infrared detector before the associated relay releases, this helps preventing the detection points releasing prematurely between rolling stock moving above.
The whole set up works remarkably well, although it’s not perfect 100% of the time!
Enjoy