broad gauge

from WordNet (r) 3.0 (2006)

broad gauge
    n 1: a railroad track (or its width) broader than the standard
         56.5 inches

from The Collaborative International Dictionary of English v.0.48

Broad gauge \Broad" gauge`\ (Railroad)
   A wider distance between the rails than the "standard" gauge
   of four feet eight inches and a half. See {Gauge}.
   [1913 Webster]