The Great 'G' Debate
Or how we got into this mess

There is little that is more confusing to the neophyte large scaler than the plethora of different scales to be found here all using the same track. Those moving up from the smaller scales are used to one physical size ratio (1:87 for HO) with various track widths for standard or narrow gauges.

Large scale has done it the other way around. -  With one 45mm track gauge serving many scales. Way back some 40 years ago a German company named Lehmann began producing very well made toy trains on 45mm track. They called it 'Gross Bahn', literally 'big train', Lehmann's Gross Bahn became known by the acronym LGB. Their early products were of German metre gauge prototypes which worked out to 1:22.5 scale which they dubbed "G-Scale", Early entries into the American market trying to lure customers from Lehmann were built to 1:24 scale partly for size compatibility reasons, partly because the math was easy.. But then some modelers began to object because that scale resulted in an odd gauge, and pushed for a different more 'correct'scale....and so it began

To try to simplify the mess, I've made up the following table. Starting with the smallest and working up.
S-1
1/32		 This scale  represents 'Standard Gauge' (4' 8-1/2") MTH, some Accucraft and Aster are build to this scale.
1/29 Supposed to be standard gauge as well, but is not - much larger and beefier. The so called "Wow" factor. Aristo-Craft and USA and Accucraft's AML line are built in this scale
1/24 Works out to 42" gauge, but many undersized 3 foot gauge models have been produced in this scale. Hartland (HLW), USA 'American' line and the Aristocraft 'Classic' line are this scale. As were the old Delton and Kalamazoo lines.
IIm
1./22.5		 Metre gauge... The narrow gauge LGB stuff was this size. Bachmann's "Big Hauler" line as well.
Fn3
1/20.3		 The 'proper' 3 foot gauge scale. Bacmann 'Spectrum' items and the Accucraft NG stuff is this scale.
SM45 (1/19) British models of 3 foot gauge, many live steam locomotives are built to this scale
7/8"=1' Represents 2 foot gauge prototypes on 45mm track. Mostly the domain of scratchbuilders

All of the above have been collectively called "G-scale" by many folks, though there are more recent efforts to separate them. 1/20.3 is called 'Fn3-scale'

Now that you think you have all that straight, I'll throw you another curve. The toymakers don't always stick to scale.... There is a LOT of 'selective compression' and just plain use of rubber rulers in large scale. The main reason was so that the new stuff being brought to market could also be used (more or less) with what folks already had (back to LGB again)... A 1/29 standard gauge 40 foot car is similar in physical size to a 1/22.5 narrow gauge 30 foot car. On some items there are even multiple scales employed on the same model to make it 'fit'. 

And stuff, sometimes from the same manufacturer STILL doesn't always look good together.

AND the icing on the cake ----- Many manufacturers don't bother to state the nominal scale of their products, leaving the customer to guess.

Hence the confusion.

Unfortunately, there are no hard and fast rules of what works with what, and what doesn't. Some folks choose to buy only from one manufacturer to try to keep things somewhat the same scale. Some run whatever looks good together, regardless of scale. And some others are happy to run a complete hodgepodge.

The best advice I can offer is, "If in doubt, measure." Generally a tape rule doesn't lie. Measure things like doors and doorknob heights, windows, and walls... In the real world this stuff falls in a pretty narrow range, --- as well as overall dimensions. If your memory is lousy, make a list of the sizes of stuff you already have BEFORE you go shopping, then keep it in your wallet. When ordering by mail or online you can ask the seller to measure it if you're not sure. If they are "too busy", then they really don't want to sell it very badly. Call another vendor.

Clear as mud? You'll think all this is 'normal' eventually.

Take me back to the AV pages