Scales and Gauges(with thanks to Alan Farthing for the suggestion and Phil Copleston for the corrections!) You will need to maximise this window to see the photos below properly. This page's contents should appear as the correct size for its scale on a 15 inch monitor set at a resolution of 1078 x 768 pixels. Interesting one this... It is a bit confusing so pay attention and ask me the difficult questions once you have finished reading all of this. First: gauge and scale - they are not the same in spite of the way they are used in the hobby. Scale is the reduction (or enlargement) of the full size object by a given ratio. A scale of 1:76 says that an object 1 inch long represents the real thing of 76 inches length. The gauge is the distance between the rails only. Standard gauge (in UK terms) is: 4 foot 8½ inch. This is the distance between the rails. Gauges can be almost anything - Brunel was famous for his 7 foot gauge (broad gauge) and the Welsh 'Little Railways' are well known for their various gauges from 2 foot 6 inch down to 1 foot 11½ inch (narrow gauge). In Ireland the gauges were 5 foot 3 inch and 3 foot, ie both broad and narrow although naturally enough the broad gauge was known locally as standard gauge! Just as there are many different gauges, there are many different scales and standards - the hobby has evolved piecemeal and techniques, materials and standards have improved enormously over the last few years leaving a somewhat confusing situation for the beginner. Taking the scale commonly known as OO gauge (in reality 4mm to 1 foot scale); this started as a table top system in about the 1920s and the gauge between the rails was set at 16.5 mm, ie 4 foot 1½ inches - effectively narrow gauge. This was to allow wider wheels to prevent the models falling off the relatively crude rails. Then came EM gauge (18 mm) with finer wheels and rails and then what became Scalefour (18.83mm). Modelling in EM or Scalefour means having to modify existing models or making your own. In the last few years the major manufacturers have been producing some stunning models (in OO gauge/16.5mm) with a newer standard of wheel and rail that is close to that used in EM gauge. Different countries have different standards or to put it another way, the Brits just have to be different! The UK - new, ready to run models are almost all in N gauge (see below) and OO gauge with some in O gauge. Rest of World - N gauge, HO gauge and some O gauge with others like S scale.
The Scales (and Gauges)In descending order of size: Gauge 32½ inch gauge (or 63.5mm) and scale is about 1/22. There is an active Gauge 3 Society, (there were larger gauges - 4 and 5 - now rare and mostly collectors items) Gauge 22" gauge (or 50.4mm) and scale of about 1:28. Largely dormant but an exhibition layout is on the UK circuit. Gauge 1 (10 mm : 1 foot)45mm gauge and about 1/30 (- Rest of World 1/32) scale with a very active Gauge One Society. 16mm scaleA 'Narrow Gauge' scale much used for garden railways hence its' other name G-Scale, 32mm gauge and 1:19 scale. O Gauge and ScaleSeven (7 mm : 1 foot)Gauges of 32 mm and 32.95 mm respectively - ScaleSeven is the 'finescale' development in O gauge. O Gauge is sometimes referred to as Gauge Nought since it was once thought to be the smallest practical. S Scale (1/64 scale or 3/16 inch : 1 foot)The UK Track gauge is 22.42 mm or as a fraction: 113/128 inch. There is an American S Gauge but has different, coarser wheel and track standards - the two are not compatible. 4 mm scale - OO gauge, EM gauge, P4 (4mm : 1 foot or 1/76.2)A peculiarly British scale... OO Gauge is 16.5 mm and it begat EM Gauge as 18.2mm and lo, thence came the prophets and they didst utter that even EM was an abomination unto the eyes of the One True Modeller and hence didst decree a whole new set of standards to a new gauge of 18.83 mm. And they were happy. Just watch out here - older OO Gauge models are not compatible with the newer track standards - only the newer models - if in doubt - get advice! HO Scale (3.5mm : 1 foot)
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| 'The oldest 'OOO', now known as 2mm scale or 2mm
Finescale, was started in the 1920s and is to consistent 1:152.4
proportion (exactly 2mm/1ft). Since the mid 1960s this uses 9.42mm gauge
(previously, 9.5mm) and supported by the 2mm Scale Association for
British prototypes. A brief early commercial flowering of 'OOO' was Lone
Star who introduced 'Push-a-Long' on 8.25mm gauge, then later a powered
'Treble-O-Electric' on 9mm gauge.' 'Next came 'N' scale in 1961, nominally to 1:160 proportion (1.9mm/1ft) and using 9mm gauge, and is now the 'world standard' for N scale (note the consistent use of term 'N scale', NEVER 'N gauge').' 'Lastly, in 1965 Peco for their own reasons 'invented' a British version of N scale running on 9mm gauge, but in an odd nominal scale of 1:148 or 2 1/16th mm/1ft. Later, Graham Farish and other British commercial manufacturers took up 1:148 scale, but have always muddled up the names of N scale and N gauge. The Americans always laugh at this as, back in the 1930s or 50s the NMRA* established the consistent use of always referring to the scale used, NOT the gauge (which may be different according to prototype - like narrow or broad gauge). The British based 'N-gauge Society' support this scale, though they started out recommending 1:152, changed to 1:148, changed back some years ago, then back again. Hmmm... no wonder the Americans find this muddle funny!' |
Z gauge
Very small and relatively expensive because of the ultra precision required - 1:220 proportion, 1.385mm/1ft and runs on 6.5mm gauge track. Kits are available.
OK, so now you know - well at least some of the story - it starts getting a bit complicated when dealing with all the narrow gauge variants. Again - if in doubt - ask!