When we talk about a model trains scale in a model railroad layout, we are referring to it’s relationship to the real thing. When we talk about “gauge” we are usually referring to the distance between the tracks rails that the train rides on. Currently the most popular scales in model railroading are O, HO, N, and Z scale. Where O-scale (1:48) is the largest and Z-scale (1:220) is the smallest.
The Scale of Your Model
The scale of a model train is the relation of it’s size to that of a “real” train. So for HO scale (1:87.1)this means that you take the measurements for a real train and divide them by 48. So 1 inch of an HO model train is equal to 48 inches of a real train. Likewise 1 inch of a N scale model is equivalent to 160 inches in the real world.
How To Determine The Gauge
The “gauge” of a rail is the distance between the rails. In North America this is 4 feet 8 inches. To determine the distance between rails for your model, simply divide 4 feet 8 inches (1422.4 mm) by the scale of your model. In the case of HO Models this corresponds to 1422.4mm divided by 87.1. This comes out very near that adopted by model train manufacturers as HO gauge.
Below are listed the scales and gauges standardized by the National Model Railroad Association for modeling standard gauge railroads.
O Scale – 1:48
Gauge: 1.25” (31.8mm)
This scale was first developed in Germany and was originally known as the “zero” scale.
HO Scale 1:87.1
Gauge: 0.649” (16.5mm)
This scale is the most popular worldwide and the designation HO stands for “Half O”.
N Scale – 1:160
Gauge: 0.353” (8.97mm)
The “N” is short for nine millimeter. N scale is the second most popular scale worldwide. N scale allows more complex layouts to be built in a smaller space than that use for HO scale.
G Scale – 1:22.5
Gauge: 1.75” (45mm)
G scale or “garden scale ”, is the largest model train scale currently available. Their large size make the G scale trains ideal for outdoors and often referred to as “Garden Scale”.
There are other scales available that you can choose to use in your model railroad layout but I’ve chosen to include only the most popular. Your choice of scale will greatly impact the amount of space you will need to devote to your model railroad layout and the amount of money you will have to spend to achieve a really great layout. You can find additional information at www.ModelRailroadLayouts.net.
