British N gauge

British N gauge
Unnumbered Peco Jubilee
Scale	2.0625 mm to 1 ft
Scale ratio	1:148
Model gauge	9 mm (0.354 in)
Prototype gauge	Standard gauge

British N gauge is a model railway scale and gauge, rolling stock is to a scale of 1:148, track is 9 mm (0.354 in) width as with all other N gauges making track and rolling stock approximately 10% out of scale with respect to each other. The 9 mm (0.354 in) track width derives from a scale of 1:160 for 1,435 mm (4 ft 8 ¹⁄₂ in) standard gauge rails.

When N gauge was developed it proved impossible to fit the then available motors into scale models of British prototype locomotives. British railways use a smaller loading gauge than those in Europe and America, resulting in smaller locomotives. A greater body size was required on the models to accommodate the motors, so instead of adopting the correct 1:160 scale, 1:148 was used. This allows larger models, but means that the gauge is not an accurate representation of standard gauge. A similar problem and solution was adopted with OO gauge and British TT gauge in Britain. However, N since it scales to approximately 4'4½" gauge it is less out of scale than OO (4'1½") or TT3 (4'0") in representing the 4'8½" standard gauge.

Finescale modellers modelling in this size use 2mm finescale, which has 9.42mm track and a scale of 1:152.