08-03-2018, 10:23 AM
This is an interesting subject. By default, detection is the absence of trains not the presence. That takes a little thinking about but the subtlety is very important.
Detection of trains is a comparatively rare thing.
1) As Dorothy states, certain LX treadles - they trigger an event based on a train striking one of them.
2) Tracks occupied for time (>=0s) - approach release for example.
3) Lime Street - checks for length of train but potentially this is also more checking for absence of trains on the other measuring tracks - a subjective argument could be had.
Am sure there are more examples but this isn't my domain... hopefully others can post some.
Detection of trains is a comparatively rare thing.
1) As Dorothy states, certain LX treadles - they trigger an event based on a train striking one of them.
2) Tracks occupied for time (>=0s) - approach release for example.
3) Lime Street - checks for length of train but potentially this is also more checking for absence of trains on the other measuring tracks - a subjective argument could be had.
Am sure there are more examples but this isn't my domain... hopefully others can post some.
Le coureur