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100:, favoured by manufacturers of British prototype models, utilised track that was too narrow. OO was developed in the UK in the 1930s as a response to manufacturers finding they were unable to fit the motors of the time into British prototype small boilered locomotives when scaled at the globally popular
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Most EM modellers will have started off using OO gauge and having acquired the necessary modelling skills, then advanced into EM. Modellers in EM typically re-wheel their rolling stock and hand-build their trackwork, although pre-built track is available from specialist suppliers. There are also many
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Attempts to make finer tyre and flange standards were thwarted initially by the overscale rail sections available commercially, it being impractical for an individual modeller to make smaller rails – although some did attempt to, by cutting down commercial rail. Smaller flange and tyre dimensions
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18 mm gauge was still undersize by almost a millimetre. With the limitations of modelling at this time, particularly the width of tyres, the largest gauge that could fit within the outline of a scale model would be 18.5 mm, no larger. This was mostly an issue for steam locomotives, where the
172:) gauge track (for a while called EEM gauge until it was adopted into the mainstream standard). Some modellers were still not happy with this, it is still a scale 1.9 inches (48.26 mm) too narrow, and developed the
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were also unsuccessful, as the narrow tyres tended to detach from the wheel centres. More critically, small flanges required comparably smaller rail, trackwork gaps and point frogs in order to work reliably.
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popular technique at the time of making connecting and coupling rods from rail required an excessive spacing between wheel faces and the cylinders.
104:'s 3.5 mm to a foot (1:87). As the scale was increased to 4 mm to the foot to make the locomotives larger, the track gauge was left at
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4 mm scale kits which can be used by all 4 mm scale gauges, and since the advanced skills, advanced kitbuilding and
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EM standards are set by the EM Gauge
Society, defining gauge and wheel dimensions to ensure compatibility across layouts.
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wheelsets based upon the crude and massively out-of-scale products of the contemporary OO model manufacturers.
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Wheelset standards did become more fine in time, allowing EM to evolve into
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141:EM gauge was founded in the 1950s, originally with
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232:. The E.M. Gauge Society Ltd. Archived from
77:(named after the track gauge of a nominal
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266:. Wild Swan Publications. p. 1.
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46:4 mm to 1 ft (305 mm)
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210:Rail transport modelling scales
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85:illimetres) is a variant of
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96:EM was developed because
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30:EM gauge locomotives by
89:(1:76) scale used in
230:"What is EM ?"
149:) gauge track and
192:are also common.
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291:EM Gauge Society
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260:Williams, R. Guy
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118:4 ft
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238:. Retrieved
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110:0.65 in
106:16.5 mm
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32:Guy Williams
114:track gauge
52:Scale ratio
306:4 mm scale
240:2009-10-06
216:References
143:18 mm
300:Category
262:(1988).
199:See also
184:gauge).
132: in
102:HO scale
98:OO gauge
81:ighteen
75:EM gauge
127:⁄
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36:Pendon
43:Scale
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