The line was on Mundallio Station (sheep station, that is), whose western boundary is at Stirling North. I should have measured the gauge - but didn't! As I remember it is about 18" gauge.
The track ran from a barites mine in a gully to a lorry loading gantry at the opening of the gully, around 500m.
While the mine is defunct, and the rails removed, the perway is distinct, and a few sleepers have escaped the termites.
The line was man-powered, and if the technology works for me, the photograph of "the wagon" will show that this is truly archaeology...
OK, so I cannot work out how to post an image...perhaps someone can PM me and tell me how!
Next question is a bit more mainstream.
At Silverton, the STCo mainline, at one place, ran between two concrete walls around twelve feet apart.