The chart below shows the six scales that are currently manufactured. By far the most popular is HO (pronounced aitch-oh). HO scale models are 1:87 proportioned, meaning one foot on the model represents 87 actual feet. An HO scale 40-foot boxcar is about six actual inches long.
The second most 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 rails. 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.
Read more about how to get started in model railroading.
The term scale refers to the size of things on a model railroad relative to things on a real railroad (see chart). For example, in the most popular scale, HO, models are 1/87th full size.
| Scale | Proportion to prototype | Approximate length of 50-foot boxcar | ||||||
| Z | 1:220 | 2¾” | ||||||
| N | 1:160 | 3¾” | ||||||
| HO | 1:87.1 | 7″ | ||||||
| S | 1:64 | 9¼” | ||||||
| O | 1:48 | 12½” | ||||||
| Gn3 | 1:22.5 | 19″ |
