Figure the scale of model trains.

People who engage in model railroading as a hobby spend hours setting up miniature tracks and environments through which to run their trains. The train models are scaled-down versions of real locomotives, and many different scales are used. The most popular scale is known as “HO,” and it is 1:87. That means a real locomotive will be 87 times longer, taller and wider than the model of it. Other scales include “Large” scale, which is 1:12; “O” scale, which is 1:48; and “N” scale, which is 1:160. If you don’t know what scale your model is, you can figure it out based on the size of the train it represents.

## Instructions

1. Place one end of a ruler or measuring tape at the center of one of the front wheels, and measure the distance to the center of the rear wheel on the same side of the train. This distance is called the wheelbase. Write this number on a piece of paper. Measure the model’s height and width, and write down the measurements.

2. Write down the wheelbase, height and width of the actual train your model is patterned after. If you don’t know the *real train*‘s dimensions, you may be able to consult a book about the train or the company that built it, or call the company and ask what the dimensions are. There is no universal database for locomotive dimensions. You may be able to find a website devoted to your particular locomotive. The simplest method may be to type the name of your locomotive model into a search engine to find a reference book or a website so you can obtain its dimensions. See Resources for some websites listing locomotive manufacturers and other railroad information to get started.

3. Multiply the wheelbase length, given in feet, by 12 to find out how long it is in inches. For example, a 100-foot wheelbase is 1,200 **inches long**. Divide this number by the number of inches of the wheelbase of your model. If **your model** is 13.8 *inches long* and the real train is 1,200 inches long, the scale is 1:87. If you don’t know the wheelbase of the real train but know the height or width, use one of those dimensions and divide by the corresponding dimension of your model. A scale model will be constructed proportionally, so you can use wheelbase, height or width to figure out the scale.