Model trains, as well as any other replica of something that exists in real life, require a scale so as to multiply the dimensions of the train that they represent. Otherwise, they would look out of proportion.
A scale is measured by two numbers, separated by a colon. The initial number of a scale tells us the equivalent of the model train. For model trains that are smaller than the trains they represent, this number is always one. The second number typifies how the 1st number would translate to the dimensions of an actual train. So, let us take for example a scale of 1:20. That implies that if something measures 1 inch on a model train, it would measure 20 inches on the real train.
HO scale trains are simply model trains that use the HO scale, which is the most common scale in nations where English is spoken.
It’s interesting to notice that HO scale trains can also be addressed H0 scale trains. The confusion started because the O scale, which is the scale HO was modeled after, was originally called 0 scale (as in the number zero). In fact, the nomenclature H0 is still used in most countries, while in the United States, Japan and Australia, those trains are addressed HO scale trains.
It’s as well important to know that the orthoepy of the “O” is “oh,” even in those countries where the terminology includes a zero. In any case HO scale trains get their name because HO scale is nearly one-half of the O scale. Hence the name “half O scale” or “HO scale.”
HO scale trains are scaled at 1:87. As mentioned above, that means that one unit on the HO scale trains corresponds to 87 units on real trains. Another, mayhap easier to fathom, way of demonstrating it, is that 3.5 millimeters (approximately one tenth of an inch) corresponds to one foot on a real train.
Because HO scale trains are so popular, there are a lot of makers, with various ranges of prices, so it is not challenging to see inexpensive HO scale trains that suit a little budget, or more costly little pieces of machinery that impress guests and beautify a room or a garden.
Lastly, like all model trains, HO scale trains require a track to move on. Tracks that are designed for HO trains are 2 railed, and powered by direct current. Owners control the speed of the train with a control that varies the voltage applied to the train. They can also change the polarity of the track, in order to make the train run in the other direction if they desire.