Scales in Model Railroad

Scales in model railroad are described by letters N, HO, S, and O. Each letter describes the ratio of the model's size to its prototype, which is what model railroaders call the real thing a model is based on.

Following six scales are currently manufactured in the market. Most popular is HO (pronounced aitch-oh). HO scale models are 1:87 proportioned, which means one foot on the model represents 87 actual feet. An HO scale 40-foot boxcar is about six actual inches long.

Scale Proportion
Z 1:220
N 1:160
HO 1:87.1
S 1:64
O 1:48
Gn3 1:22.5

The second popular modeling scale is N scale with a ratio of 1:160, it's a little more than half the size of HO scale. An N scale 40-foot boxcar measures just over three actual inches long.

Many model railroaders use the terms "scale" and "gauge" interchangeably, but they really mean different things. Scale, as we already learned, is the ratio of the model to the prototype. Gauge is the distance between the rail tracks. Standard gauge on North American railroads is 4'-8½", but many railroads, especially in the 1800s, were built to narrower gauges. Three feet between the rails was the most common narrow gauge in the United States. To indicate narrow gauge models we use a small "n" and the gauge of the track prefaced by the scale. For example, an HOn3 layout is one where the buildings, figures, and trains are HO scale, but the rails are spaced three (scale) feet apart.