Never looked into Dogman specifically but this ties in with something I've been chewing on for years - old rail lines and ley lines often run parallel or even overlap in certain parts of the country. Round here near Salisbury there's an old disused line and the energy readings I've picked up doing EVP work nearby have always been off the charts compared to other locations.
Whether thats attracting something or the geography itself is the reason both the rails and the phenomena ended up there, I genuinely don't know. Old rail routes often followed the path of least resistance through the landscape and so did ancient trackways. Could be the same logic at work.
Has anyone actually mapped the sighting locations against railway atlas data? That feels like something worth doing properly rather than just going on impressions. Would be curious to see if teh pattern holds up under scrutiny.