Three major global hobbies should be compatible with each other, but are not. Scale Modelling, Railway Modelling, and Military Modelling / Wargaming conflict in model scales.
This guide is to assist participants in each hobby with crossing the scale divide, in order to buy and sell to each other, and to make use of resources available in the hobbies which are not their own.
Please note - this guide is about scale, not about track guage for railway modellers. It is primarily concerned with the size of medels and their compatibility between hobbies, for that reason, railway scales are stated as scales, not guages.
Arranging the most commonly used scales from smallest to largest, we find the following variants (millimetre scale in parentheses is the nominal height of an average man (6-foot or 1.85m) at that scale - not the size per 12 inches as used by railway modellers)
1:3000 - A micro-naval scale used by wargamers yielding models of the world's largest warships as only an inch or two long.
1:2000 - Another micro scale for naval wargaming
1:1200 - A favoured scale for "Age of Sail" and Ancient Naval wargaming.
1:600 (2mm) - Another micro scale also used by wargamers, most commonly for coastal/inshore naval wargaming.
1:300 (6mm) - The most popular micro scale for wargaming, especially for land battles.
1:285 (6.5mm) - A scale originating from the plastic kit modelling world. Some wargames micro manufacturers launched their first ranges in this scale (e.g. Skytrex WW2 micro) before companies such as Heroics & Ros launched their ranges in 1:300 and moved the whole industry down 1mm. Some of Skytrex's models have not been redesigned down, and are still slightly overscale for 6mm.
1:220 (9mm) Z-scale - A popular railway modeller's micro-scale and potentially the trigger for the 10mm wargaming scale.
1:200 (10mm) - Strictly speaking this is 1:185 scale but hobby convention ties 1:200 as being 10mm. It is an intermediate wargaming scale that first came to popularity in the late 1980s / early 1990s. It allows the detail of larger scales with the cost saving of the micro scales.
1:185 (10mm) - see 1:200 above.
1:160 (12mm) N-scale - A popular small-scale for railway modellers allowing large affordable layouts with good detail.
1:144 (13mm) - A popular collector's scale for die-cast models from Japan, it also appears in cheaper versions from China, and used to be popular in plastic kits (though offerings in kit-form seem to be thinning out - Tamiya still produce a limited catalogue). It has never truly had a following in either railway modelling or wargaming, despite being closely compatible with N-scale (above) and true-15mm (below).
1:120 (15mm) - The most popular scale for wargaming in Europe, it allows significant cost savings over larger scales, superb detailing in models and figures, and has the largest support from figure designers and manufacturers. With the exception of a few long-established names, most manufacturers are still small businesses though, and the supply-side of the industry has proliferated in recent decades, diluting the opportunity for all. Railway modellers should investigate wargaming's True Scale 15mm wargames buildings as they work superbly with N-scale layouts, but beware of designers who are actually designing for 18mm figure compatibility (below).
UPDATE (22 Jul 2006) - According to rail model manufacturer Digitrax, 1:120 is TT scale (above) and 1:100 (below) is TT3 scale - anyone got further info on this?
1:100 (18mm) TT-scale - Although around for a long time in plastic modelling kits, the 18mm scale has emerged in the wargames market by accident, and does not seem popular with railway modellers. Early Minifigs 15mm white-metal figures were designed overscale (especially the Ancient Roman and Greek ranges). With time, a lot of the "new bunch" of designers were designing over-scale with men standing at 18mm high but being sold as 15mm scale. Today, scenics and buildings manufacturers designing at true 1:120 scale often find customers complaining that their products are under-scale for 15mm, when in reality, it is the figures that are overscale.
1:96 (19mm) - A long time popular scale with Japanese plastic kit manufacturers, especially the early producers of WW2 models. It also had a popularity with die-cast manufacturers, but appears to be dying away now in favour of other scales.
1:93 (20mm) - Another scale that appeared around the same time as 10mm in the wargames hobby. It has it's followers, but is not "in the mainstream", although many manufacturers devoted a lot of investment into it - initially with mostly WW2 ranges (it was very popular for WW2 North African gaming for quite some time, as was 10mm). There are some stunning examples of model design amongst the white metal designers in this scale - rivalling the 25/28mm design quality.
1:87 (21mm) HO-scale - perhaps the inspiration for the wargaming 20mm scale. HO has been the mainstay of railway enthusiasts for a long time and has a huge support from designers and manufacturers - almost every rail model producer supports HO, and often products are labelled as HO/OO showing a tendency to design in either over or under scaling for those two - Airfix is an example where they often label 1:72 scale models with a second tag stating "HO/OO scale" (see below).
1:77 (24mm) OO-scale - (Ok put your arguments away - in all the other scales a 6-foot man is calculated as 1850mm, I've kept it the same here, divide 1850 by 24 and you get 1:77 - at 4mm per foot OO-scale, that is 24mm per man-model height). Another of rail modelling's most popular scales, a lot of OO-scale accessories can transfer to 25mm wargaming and vice-versa. OO has huge support from model railway manufacturers. Almost all manufacturers tend to dual label this scale as "HO/OO" and leave it to the customers to decide which scale they will use it with.
1:72 (25mm) - The grand-daddy of all modern modelling scales. The original scale of all Airfix models, both platic assembly kits and figure sets, it has spread around the world as the largest production scale range available. Not surprising then that many metal-figure, wargames designers cut their artistic teeth in this scale. Unfortunately, like 15mm, it is suffering from "over-scale design syndrome", largely thanks to the influence of Games Workshop and Ral Partha during the 1970s and 1980s - kids who grew up on "big" hero models wanted the same when they migrated to "real" wargaming, and took their Citadel figures with them. By the 1990s, the wargaming industry saw the writing on the wall and 25mm became 28mm, with companies such as Wargames Foundry, Dixons, et al leading the defection.
1:66 (28mm) - The new kid on the block with "designer games" at the forefront - Games Workshop / Citadel have always used 28mm as a product protection process (other manufacturers figures were originally non compatible in the smaller 25mm scale), but many mainstream wargames figure makers have moved up 3mm since the 1980s.
1:64 (29mm) S-scale - A once-popular railway modelling scale that does not see so many offerings nowadays, and potentially the inspiration for the 28mm scale (above) when Games Workshop broke away from 25mm.
1:48 (39mm) O-scale - The entry-level large-scale for railway modelling, it has no real equivalent in wargaming, but a strong supply from the plastic kit industry.
1:32 (58mm) - Another popular plastic kits scale, as well as a scale favoured by plastic soldiers. 1:32 is the correct ratio for Railway modelling gauge-1.
1:22.5 (80mm) G-scale - I've now been informed that this is the correct ratio for G-Scale (sorry for any earlier confusion).
The author operates eBay ID GazLanNaThai, and is the designer of the Long Range Logistics & Small World Scenics model buildings ranges, in addition to being South East Asia Correspndent for Miniature Wargames magazine.