49 CFR 213.323 - Track gage.
(a) Gage is measured between the heads of the rails at right-angles to the rails in a plane five-eighths of an inch below the top of the rail head.
|Class of track||The gage must be at least—||But not more than—||The change of gage within 31 feet must not be greater than—|
Title 49 published on 2014-10-01
no entries appear in the Federal Register after this date.