Interesting pattern and one I've been quietly tracking for a while. The old Shrewsbury to Aberystwyth line has had at least three credible reports in the last decade that I'm aware of, all within about two miles of the old permanent way.
My working theory - and I know this will get some eye-rolls - is that the embankments and cuttings create sheltered wildlife corridors that these things use for movement. Old railway infrastructure also tends to sit on marginal land that doesn't get much human attention, so whatever's out there gets left alone.
The psychic angle interests me more though, which is my particular corner of this field. Several of the witnesses I've corresponded with describe a strong sense of being watched well before the sighting, almost like a pressure in the head. That suggests something beyond simple cryptid biology to me. Has anyone mapped the old rail lines against ley alignments? Because I have a hunch there's overlap there that nobody's properly documented yet.