After the demise of the previous Invisible Train, H Hunter and myself wanted to celebrate another old abandoned part of Glasgow's railways, at Thornwood Park, where you can still see remnants of the Tunnel. There have been modern flats built over most of it now, but you can see the bricked over tunnel entrance in Crathie Drive, nearby.
Flats overlook the location, so beware of muggles. And thorns. Bring a pen.
More information:
http://www.hiddenglasgow.com/forums/viewtopic.php?f=15&t=848
http://glasgowpunter.blogspot.com/2017/09/disused-train-lines-and-ghost-railway.html
---update after a few DNFs the original cache seems to have been removed, now replaced. Please ensure that it is hidden as originally found.