Here are 3 other off-the-shelf isolated-rail-trigger relay modules that have been discussed in the last month or so on OGR. If anyone else has photos or diagrams to add of other off-the-shelf relay modules, it might be useful to consolidate tack that on here (for the record).
Azatrax MRAPR and Lionel 153E shown below in photo from another thread:
https://www.azatrax.com/track-power-relay.html
The 153E seems to be discontinued or very hard to find. The Azatrax does not appear to have a capacitor on it but I don't have one so don't know for sure.
Train Electrics MTR-12T
http://www.trainelectrics.com/relays.html
If with roll-your-own, here's a write-up by Dale H about what's going on under-the-hood at the component level which has photos of his implementation:
http://www.jcstudiosinc.com/Re...Rail-Block-Detection
And here's GRJ's schematic I copied from this thread where he posted it. He might have a photo of it somewhere but I can't remember.
