H0 scale as we now know it was developed in Britain in the mid 1920s by members of the Wimbledon MRC as 3.5 mm/ft on 16 mm (later 16.5 mm) gauge track, and eventually adopted by almost the whole world but not by the country where it began. This blog post is a simple account of the milestones in the development of H0 scale, written up mainly for modellers of British railways who are considering tackling a small layout in the scale, and the modest number of people who already do. I am very grateful to three members of the RMWeb – David (“Pacific231G”), Kevin (“Nearholmer”) and John (“Allegheny1600”) who posted up a great deal of the content here in a short exchange of posts in a topic dealing with 00 gauge, in the Spring of 2018.
H0 scale is quite an old scale, and Bassett-Lowke is quoted as saying he had the idea for producing half 0 gauge model trains in the 1900s but unfortunately the "great war" got in the way after 1914.
In 1922, Bing (of Germany) started making small model trains, in close cooperation with Bassett-Lowke. The models were quite toy-like and so the scale seems rather vague, but the gauge was nominally 16 mm or 5/8”. There is a representative display at Brighton toy museum. Some time later, modellers started to add an extra 0.5 mm to the gauge. In those days 3,2,1, 0 and indeed 00 always referred to the gauge and were generally referred to as no. 1, no. 0 or no. 00 gauge and so on.
In around 1923/24, Stewart Reidpath, A.R. Walkley and M. Longridge (all members of the Wimbledon MRC) settled on a scale of 3.5 mm/foot (1:87 scale), which is, of course, half of British 0 gauge’s 1/43.5 and 7 mm/foot.
Henry Greenly championed a scale of 4 mm/ft for 00 gauge to allow for the 3.5 mm wide tyres (5 mm wide wheels) he considered necessary and stated very firmly his opinion that "the gauge is not the correct method of arriving at the scale". It certainly wasn't for the locos he designed for the Ravenglass and RHDR. There seems to have been an assumption on his part that most modellers would continue to rely on semi-portable track rather than laying it on baseboards, and that 00 would be a table-top equivalent of 0 gauge with equally tight curves rather than a gauge for broader scale modelling.
By 1925, when the Model Railway News first appeared, the public debate between those going with Greenly's 4 mm/ft scale, especially Greenly himself, and those looking for scale models and going for 3.5 mm/ft scale seems to already have been in progress. Both approaches were of course designated “no. 00 gauge”.
Actual models using this 00 gauge were still fairly rare and layouts featured in the magazine were as likely to be 1 gauge as 0 gauge. In the magazine’s first year only eight physical models for 00 gauge appeared with photographs rather than as just drawings, and six of those, including two layouts, were 3.5 mm/ft scale.
Nevertheless, 3.5 mm/ft scale was consistently adopted in North America and throughout continental Europe, and almost completely abandoned in favour of 4mm/ft scale in Britain, between 1926 and 1939. The designation “H0” became associated the smaller scale, and “00” became associated with the larger scale. There is a detailed write-up of the development of 00 at the web site of the Double O Gauge Association.
In 1935, the National Model Railroad Association (NMRA) was founded in North America, and later the organisation chose to define H0 scale as 1:87.1. This is 3.5 mm/ft written to one decimal place rather than rounded down to an integer - the difference with 1:87 is negligible for practical model-making. The NMRA publishes many standards and recommended practices, and some of these are useful for modelling British H0.
Meanwhile in Continental Europe, some French modellers used 1:86 scale and referred to it as “00”, while some German modellers proposed a scale of 1:80. In 1952, an agreement at the Ruedesheim Conference of European Model Railways Associations decided that the scale of H0 would be 1:87 and its gauge 16.5 mm. The Conference became an annual event and a couple of years later it agreed to set up an "Organization of the Model Railway Friends Europe" (MOROP) as an international standards body registered in Switzerland. MOROP later changed its full name to “Organization of Model Railroaders and Railway Friends Europe".
MOROP is formed by several of Europe's national model railway associations. Writing this up in March 2018, there are 21 members from 16 countries in Continental Europe, and none from the UK. The organisation publishes the NEM series of standards ("norms of model railroaders"), and again some of these are useful for modelling British H0.
There are a few RTR railway models described as H0 but built to a different scale, most notably by Rivarossi (Italy) whose European prototype models were for a time to 1:80 rather than 1:87 scale - though their contemporary US prototypes were to 1:87 scale. The British outline models by Rivarossi and also Trix Twin (Germany) were around 1:80 scale. The usual German scale for no. 0 gauge was (and still is) 1:45, and this may explain why some other (older) German “H0” models were made to 1/90th scale.
Japan is an interesting case, where both 1:80 and 1:87 scale are used to represent 3ft 6in gauge trains on 16.5 mm gauge track, and the models are all described as “H0”. It is unclear why the Japanese didn't adopt 1:87 scale with 12 mm gauge track, which is actually closer to 3ft 6in gauge than it is to the metre gauge it's normally used for as H0m. In practical terms, N gauge is far more popular then the local versions of H0, because there is so little space in Japanese homes.
Some model buildings and kits marketed as “H0” are closer to 1:100 scale, but these are departures from the accepted scale of 1:87 rather than different flavours of H0. There are examples from Jouef, Noch and Faller. The use of a smaller scale is similar to the way some model buildings sold for 00 today in Britain (like some items in the Bachmann ‘Scenecraft’ range), are actually to 1:87 scale.
I have omitted mention of the BMRSB here, partly for clarity but mainly because I cannot find anything pertinent to the present-day modeller of British railways in H0. This leaves the modeller with two sets of popular standards to choose from: those of the NMRA and those of MOROP. Essentially, the production of most Peco track is driven by the market in North America, while most of the RTR rolling stock finding its way onto a British outline layout has its origins in Europe; and both work happily together.
At a personal level, British H0 is engaging me in the hobby far better than my prior efforts in most of the popular British scales and gauges. I hope to write fresh things about British H0 as I gain experience with my own model-making and layout, usually with specific models and occasionally with more general posts like this one. In the meantime, these notes will be the introduction to my blog.