3. Scale and Gauge
Scale and gauge are two important terms that have caused a lot of confusion over the years, and will no doubt continue to do so. They are sometimes used interchangeably, though incorrectly.
It really is quite simple: Scale is nothing more than the proportion of the model to the full size train. This can be expressed as a fraction or a ratio (as in 1:24 scale) or as the scale's relationship to a foot (like 1/2" to the foot, or just 1/2" scale). Gauge is simply the distance between the rails, measured from the inside edges. Where it becomes confusing is when we begin to see all of the different scales -- many of them very close to one another -- that are used with the different gauges.
There are many, many possibilities. LGB is 1:22.5 scale -- also called G scale -- and it runs on No 1 gauge track (45 mm between the rails).
Today the term 'Garden Railway' or 'G Scale' is normally applied to Gauge I, IIm or SM32 and SM45.
Gauge I, IIm or SM32 and SM45.
Gauge 'I', though using the same 45 mm track gauge as IIm scale, is quite different - Gauge '1' models are of standard gauge railways while IIm Scale models are of narrow gauge railways.
IIm scale, SM32 and SM45 are normally grouped together as size compatible, despite the scales being slightly different. Though they have two different gauges, 32 mm and 45 mm, all three represent narrow gauge models and have similar overall sizes of locomotives and stock. In the USA they have 1/2" and 5/8" scale narrow gauge using 45 mm gauge track which can be run along side the above mentioned.