Honestly not surprised this is getting more attention. Old rail corridors are basically liminal corridors by definition - abandoned infrastructure, disrupted land, residual electromagnetic weirdness from decades of heavy machinery. If anything's going to use those as travel routes or... bleed through from somewhere else, railways make complete sense.
Down here in Cornwall we've got decommissioned mineral tramways everywhere and I've had some genuinely odd experiences along the old Redruth & Chasewater route at night. Nothing I'd slap a "Dogman". Label on specifically, but the presence feeling is distinctly different from your standard wildlife encounter. My K-II meter goes absolutely mental in certain spots that have no obvious EMF source.
The rail line theory also fits with the liminal space hypothesis - that certain transitional zones act as thinner membranes between dimensional states. Dogman could be an interdimensional entity using these corridors rather than a purely physical cryptid.
Few questions worth exploring as a community:
Are the sightings clustered near active lines, decommissioned ones, or both?, Any correlation with specific geological features underneath? Old Cornwall sightings tend to cluster over granite, Time of sightings - are we seeing a pattern around dusk/dawn transitions?
Would be interested to see if anyone's mapped this properly rather than just collecting anecdotes. Someone with access to a decent GIS tool could do something genuinely useful here.
What regions are people reporting from?