Getting into model railroading can be confusing because of the number of popular model railroad track gauges and modeling scales. Here is some basic information on gauges, scales and some other model railroad terms.
Gauge - The gauge of the model railroad refers to the distance between the two rails. So if you get out your calipers and you measure the distance from the inside of one rail to the other rail, that is the gauge. I did this with our old Lionel electric toy train set from the 1960s and I measured 1.26 inches. Don't worry... you don't need calipers and don't worry about any rail that may run inside the two outside rails. The inside rail has nothing to do with the gauge. My 1.26 inch track would be "O" gauge track which is nominally 1.25 inches ( 1-1/4 inches) from the inside of one outermost rail to the other. Here are how the gauges compare:
You may find it interesting that the term "prototype" is used by the railroad modeling community to refer to the life-size train after which a model is patterned. If you have a background in product design this may seem like a strange term to use for real trains that were produced. However, from a modeler's perspective the real train is the thing that serves as a model (a prototype) for the purposes of producing a scaled-down model. The real train is the original (prototype) object that a modeler studies. This term is also used for all other life-size objects in model railroading such as buildings, automobiles, scenery, etc.
Scale - Scale refers to the proportion that a model bears to the thing that it represents. Model railroading "scale" is relative to "life-size" (prototype) objects. Of course, you can make a model in any scale that you want. Here are some scales in model railroading that have been given names with their corresponding proportions ( ratios ) to prototype objects.
Well... now you are probably really confused. You better just get out to your local train hobby store or a train show. Meet some people and have some fun! There is probably an active model railroad club near you too.
Comments or suggestions? email firstname.lastname@example.org