N scale is a popular moel railway scale/track gauge. Depending upon the manufacturer (or country), the scale ranges from 1:148 to 1:160. In all cases, the gauge (the distance between the rails) is 9 mm. The term N gauge refers to the track dimensions, but in the UK in particular N gauge refers to their 1:148 scale, 9 mm track gauge modeling. The terms N scale and N gauge are often used interchangeably. An advantage of N scale is that it allows hobbyists to build layouts that take up less space than HO scale, or put longer track runs into the same amount of space, because the models are smaller (by nearly a half) than they are in HO scale (1:87). The name comes from an abbreviation for Nine millimetres, which is the distance between the inside edges of the rails. N scale however, is not the smallest commercially available scale, as Z scale is smaller yet at 1:220.