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Monday, April 7, 2014

A Quick Tip

I need this constantly, and I'm sure many others do as well.  Let's say you want to build a narrow gauge model.  You'll need to find out what the actual gauge is supposed to be.  So below is the following formulas I use to determine either the gauge of the model, the prototype gauge, or the scale of the model:

The first equation  I typically use for determining the gauge of the model I'd need to use to represent a specific prototype gauge.  On30 uses HO scale track to represent 30 inch gauge track, Fn3 uses G scale track to represent  36 inch gauge, Gn15 uses HO scale track to represent 15 inch gauge.

The second equation I don't use often, but in certain cases, it's good to identify the gauge of the prototype based on the model.  For instance, an On30 Locomotive runs on track about .625 inches apart; the prototype runs on 30" gauge track.  But did you know that 1/29th scale models running on 1.77 inch track actually represents a prototype track gauge of 51 inch , less than the actual 56.5 inch (standard) gauge.

The Third equation I use often when trying to determine what scale I'd need to build a model based on a set gauge.  For instance, let's say you want to represent an 18 inch gauge prototype using HO scale track (.625 inch).  To find the scale I'd need to use, I use the above equation to work out that I'd need 1/29th scale figures, cars, buildings, etc...  If doing this equation on a calculator, you will come up with a weird decimal.  To convert to a scale ratio, take 1 and divide it by this decimal, then round t the nearest whole number.  The above example would show 0.0347222... on the calculator.  If I take 1 divided by 0.034722 I'd get about 28.8.  I then round up to 29, so I need to model in 1/29th scale using HO scale track to represent 18 inch gauge.

While many won't need to know this, it helps for people looking for odd scale, gauge combinations that aren't normally sold RTR and need to be kit bashed or built from scratch.


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