Really interesting pattern you've picked up on there. I'd not made that connection before but now you mention it, there does seem to be a clustering of reports around old infrastructure corridors - not just railways but canal towpaths too, at least from what I've read about UK sightings.
My thinking on why that might be the case:
Wildlife corridors - old rail lines are often left to go feral, dense vegetation, minimal human disturbance. Perfect territory for something large to move through undetected, Liminal spaces - there's a long history of strange encounters in transitional zones. Railways cut through landscapes in unusual ways, sometimes disturbing very old ground, Acoustic properties - metal rails, tunnels, embankments all do strange things to sound. Could explain some misidentifications, though not all
I've been doing EVP work near an abandoned stretch of track outside Birmingham recently, not specifically looking for Dogman evidence but the atmosphere is genuinely unsettling after dark. Got some unusual audio I'm still trying to analyse.
What I'd find useful is if people could map their sightings more precisely - specifically whether the encounters happen on active lines, disused lines, or just near old railway land. That distinction matters if we're trying to build a proper picture.
Has anyone cross-referenced the UK Dogman reports with Ordnance Survey historical railway maps? Feels like that could surface something concrete rather than just anecdotal patterns.