Interesting pattern to flag up. I've been doing EVP work out near some of the old Oregon-Pacific corridor remnants and honestly the acoustic properties of those routes are unusual - long flat clearings, embankments that channel sound in weird ways, and a lot of residual infrastructure that animals use as travel corridors. Nothing specifically "Dogman" but I've captured some vocalisations I can't readily attribute to coyote or black bear that correlate with those zones.
My boring practical take is that railroad grades follow terrain logic - lowest gradient paths through difficult country - so wildlife naturally uses them too. Whatever people are seeing, the sightings clustering near lines probably reflects animal movement patterns more than anything mystical.
That said I'm not dismissing the broader correlation. Would be genuinely curious if anyone has mapped the specific lines involved and cross-referenced with old settlement or logging history. Some of those corridors haven't had regular human traffic in decades and thats a lot of undisturbed territory. Anyone actually done a proper overlay or is this still at the "I noticed a thing" stage?