Regina Railway Modellers Association
There are many scales in which you can model trains. The smallest common scale is Z scale (1:220) and the largest indoor scale is G scale (approx. 1:24). The three most common scales are HO, O and N scales. The table below lists each scale and its ratio (e.g. 1:x where 1 inch on the scale model represents x inches in real life).
Let's say we have a GE ES44AC model. This is a photo of the real thing used to illustrate scale.
The table below lists each scale and its ratio (e.g. 1:x where 1 inch on the scale model represents x inches in real life).
SCALE


RATIO


SCALE


NOTES

Z


1:220


1/16 inch to 1 foot



N


1:160


5/64 inch to 1 foot



TT


1:120


3/32 inch to 1 foot



HO


1:87


1/8 inch to 1 foot



S


1:64


3/16 inch to 1 foot



O


1:43/1:48


1/4 inch to 1 foot


1/43 in Europe; 1/48 in North America

G


1:22.5


1/2 inch to 1 foot


Size varies according to manufacturer








HOn3


1:87




HO scale rolling stock on narrow guage (N scale) track

On3


1:43/1:48




O scale rolling stock on narrow guage (HO scale) track
