The phrase "narrow gauge" refers to a type of railway track that is narrower than the standard track width. It is used to describe a smaller distance between the two rails on which trains run. Full definition
Here you will have the opportunity of travelling on a historic narrow gauge railway. (go4less.ie)
Painting isn't about the new, you know, and it's not about novelty, because everything in painting has a very narrow gauge. (artspace.com)
Durango & Silverton Narrow Gauge Railroad runs 45.4 miles between Durango and Silverton from May through October, and 26 miles between November and May (ending at Cascade Station). (petergreenberg.com)