The block ‘occupied’ status and the corresponding highlight colour only appears as long as the block occupancy sensor is triggered. When working with momentary sensors, like I do with reed switches and magnets, the occupied status flickers as many times as the sensor triggers. Just because one reed often switches two times when a magnet passes over it and also bacause I have multiple magnets under my trains, like on the last wagon, used for driving backwards.
Page 138 of the user manual warns against potential problems when sensors are triggered multiple times by the same train. Although with me TC never got confused and traffic flow was error free, the messages window showed warnings of sensors being triggered when not expected.
Well … I can’t avoid multiple triggers with my sensors … but there are ways to trigger the block occupancy indicator just once, like is advised. This is done by not using the sensor directly inside the block, but by using a Flagman in the block.
On page 292 of the manual a method is described using 2 detectors and a Flagman with its memory on ‘toggle’. This method won’t work for me, since I have only one sensor per block! Also my sensors are triggered more than once, which means this flagman will get toggled multiple times. This is not going to work reliably, I need to find another solution.
What I did is to use switches (one for every block, two for every 2-directional block) on the switchboard as an intermediate ‘memoty’. It is switched on by the sensor, which is now an ‘external’ sensor, it does not reside inside the block anymore. A Flagman is used inside the block, it is triggered by the switch and this Flagman now determines the ‘occupied’ status.
The advantages are:
– The switch is switched on only once, no matter how often the sensor is triggered
– the flagman therefore is triggered only once … absolutely no more multiple occupancy triggers
– the switch can be put off with any occurrence which we can choose ourselves. I chose to do it when the train reaches the stop marker of the block, that way I also can see if a train is driving (occupied is on) or stands still (occupied is off).
Combined with the block release Rule put on ‘Smart or upon Entry’ this gives nice early release of blocks and a nice flow of trains on the layout, see next video nr. 37 for more on this.