Genuinely interesting pattern you're pointing out here. I've been cross-referencing a few sighting databases and there does seem to be a clustering effect near old rail corridors - particularly abandoned lines that cut through woodland.
My thinking is it's probably less about the tracks themselves and more about what rail lines historically did to the landscape. They carved straight paths through dense forest, created wildlife corridors, and then got abandoned - leaving overgrown stretches that are basically perfect cover. Old embankments, culverts, drainage tunnels. If something large wanted to move without being seen, that's prime real estate.
The Swansea area has a few disused lines and I'll be honest, walking some of them at dusk gives me the creeps in a way that's hard to explain rationally. Whether that's atmosphere or something else, I couldn't say.
Has anyone actually mapped sightings against old OS rail maps?
That would be worth doing properly. The BSRC database has enough UK reports now that you could probably run a basic proximity analysis. Someone with actual GIS skills would need to take it on though - my technical abilities stop well short of that.
Also worth considering: infrasound. Old tunnels and cuttings can produce low-frequency sound in certain wind conditions. Could explain the dread people report before sightings rather than the sightings themselves.
What regions are you seeing the strongest clustering in? US reports or UK as well?
