Prototypes, USA - Homestake Mine
This article was published May 17, 2012.
Homestake Mine in Lead, South Dakota. Big article in Gazette 1984 March/April issue. This mine had 22in gauge on surface and 18in underground, but later switched to the 18in "mine standard gauge" on all there tracks.
This page needs more editing. I will collect what I have at a later date.