2 mm scale, often 2 mm finescale is a specification used for railway modelling, largely for modelling British railway prototypes. It uses a scale of 2 mm on the model to 1 foot on the prototype, which scales out to 1:152. The track gauge used to represent prototype standard gauge is 9.42 mm. Track and wheels are closer to dead scale replicas than commercial British N.

N scale is a popular model railway scale. Depending upon the manufacturer, the scale ranges from 1:148 to 1:160. Effectively the scale is 1:159, 9 mm to 1,435 mm, which is the width of standard gauge railway. However the scale may vary to simulate wide or narrow gauge rail. In all cases, the gauge is 9 mm or 0.354 in. The term N gauge refers to the track dimensions, but in the United Kingdom in particular British N gauge refers to a 1:148 scale with 1:160 track gauge modelling. The terms N scale and N gauge are often inaccurately used interchangeably, as scale is defined as ratio or proportion of the model, and gauge only as a distance between rails. The scale 1:148 defines the rail-to-rail gauge equal to 9 mm exactly, so when calculating the rail or track use 1:160 and for engines and car wheel base use 1:148.