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Re: [7mm NGA] French NG - longisgh post

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  • david THOMAS
    John Dennis wrote ... I don t understand this. On30 is to a scale of 1:48, using a 16.5mm track gauge. O-16.5 is 7mm scale (1:43) also on 16.5mm gauge track.
    Message 1 of 1 , May 1, 2008
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      John Dennis wrote
      >Peter
      >The whole issue of scale and gauge becomes (in my tiny mind) even more
      >confusing when you switch to NG.
      >O scale is 1:43 but O-16.5 works on 1:35 scale track and the continental
      >On30 is 1:30 – so all the time it’s compromise.

      I don't understand this. On30 is to a scale of 1:48, using a 16.5mm
      track gauge. O-16.5 is 7mm scale (1:43) also on 16.5mm gauge track.
      The Continental (European) designation for this is Oe, which also uses
      16.5mm track but at 1:45 scale.>>

      There's never been a common standard in the UK so we've had OOn3, 009, O
      16.5, On15, O 9 and so on, but in America and Europe things have been
      codified by the NMRA ans MOROP but on different principles.

      For narrow gauge, the NMRA system uses the format of a lower case n followed
      by the prototype gauge so On3 is a model of a three foot gauge railway in
      American O scale which is 1:48. On30 is a 2'6" gauge railway and On2 is a
      two foot gauge railway. The gauge is supposed to be exact for the scale so
      that for example in HOn3 the gauge generally used is 10.5mm (though most
      people modelling two foot gauge railways in HO scale seem to have used 9mm
      gauge track) North America had relatively few gauges in common use so these
      three cover most narrow gauge railways.

      The MOROP system for narrow gauge (set out in NEM010) is rather different as
      it uses the standard gauge from a smaller scale (and therefore with wheels,
      chassis and track components commercially available) to represent a range of
      narrow gauges and uses a suffix of m (metre but including everything
      850-1250mm) e (etroite for gauges around 750mm between 650-849mm) and f or i
      (feldbahn or industriel for gauges between 400-649mm)

      So, Om borrows 22.5mm gauge from S scale. Oe uses 16.5 gauge borrowed from
      HO and Of (known as Oi in francophone countries) uses 12mm gauge to
      represent the most common 600mm industrial gauge as well as other gauges
      around that.

      MOROP defines O scale as 1:45 but with a note that in certain countries the
      scale used is 1:43.5. The French have always used the same scale as us for O
      whereas the German manufacturers went for 1:45 but I don't know which scale
      is most commonly used in the other European countries.

      The MOROP system is a compromise but with at least twenty narrow gauges in
      use through Europe it does enable modellers to use commonly available
      components to represent them. Neither system precludes individual modellers
      from using any scale and gauge they like so that Gordon Gravett, who is a
      scratchbuilder par excellence, chose to use the 1:50th scale commonly used
      for architectural models and then used EM gauge track and wheel standards.
      Having seen the end result on Pempoul who'd argue with him?
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