Model Train Scale & Gauge

The scale of a model train refers to the relationship between the size of a model train and the prototype.

Scale/Model Size

Most popular scales of model trains, G, O, HO and N.

Dimensions of model train in various scales are shown in the following table (in inches):

SCALE
RATIO
GAUGE
LENGTH
HEIGHT
G
1:22.5 to 25
1 ¾"
26.7"
6.0"
O
1:48
1 ¼"
16.1"
3.6"
HO
1:87
5/8"
8.9"
2.0"
N
1:160
3/8"
4.8"
1.1"

The scale is expressed as a ratio, for example, 1:87, for HO scale. HO scale model is 1/87th as large as its prototype.

Gauge/Track Size

The gauge refers to the size of the track on which the model trains operate. Gauge is the spacing between the rails and code refers to rail height.

Scale

G Scale - G is the largest of the popular scales, 1:22.5 to 1:25. Also includes #1 gauge, 1:32. G scale is also known as the Garden scale, as these trains are frequently operated outdoors. G gauge track is about 1 3/4" between the rails.

O Scale - O scale is 1:48, roughly half the size of G scale. O gauge track is about 1 1/4" between the rails.

HO Scale - HO scale is 1:87, close to 1/2 the size of O scale. HO gauge track has rails a bit over 5/8" apart.

N Scale - N scale is the smallest 1:160, a little over half the size of HO. N gauge track has the rails just under 3/8" apart.

SCALE	RATIO	GAUGE	LENGTH	HEIGHT
G	1:22.5 to 25	1 ¾"	26.7"	6.0"
O	1:48	1 ¼"	16.1"	3.6"
HO	1:87	5/8"	8.9"	2.0"
N	1:160	3/8"	4.8"	1.1"