Mate this is something I've been quietly tracking for about three years now and the correlation is genuinely hard to ignore. Old disused lines especially, not the active freight ones. There's a stretch of decommissioned track out in rural Victoria that's had four separate reports in the last 18 months and all of them describe the same basic silhouette crouching near the embankment at dusk.
My working theory - and I know this sounds a bit out there - is that railroad corridors function as established wildlife movement routes, so anything large and territorial would naturally follow them. Whether that explains a bipedal canid is another question entirely.
Anyone got reports from the Hunter Valley lines up in NSW? I've seen a few things mentioned in passing on other forums but never any proper documentation. Also curious whether the sightings cluster around specific infrastructure like bridges or tunnels, because that pattern would be pretty telling if it holds up across multiple locations.