Thanks for explaining that one Ross.
Still no bloody wiser
Rob
Ok try this.
Gauge 0 is 1:43.5 or 1:45 scale in Europe and 1:48 in the US 32mm ish track depending on exact scale
Gauge 1 is 1:32 or 1:29 scale in US and runs on 45mm track and is called Spur I, Spur 1 or Spur eins in Germany, note US locos run on 45mm track so are in effect narrow gauge, their correct gauge would be 50.8mm.
Gauge 2 is 1:29 scale and runs on 50.8mm track and used to be the dominant one in the US but as the gauge is close to Gauge 1 then it dropped into that scale and has become virtually redundant.
Gauge 3 is 1:22.5 scale and runs on 63.5mm track, it is called 2½" gauge over here and usually reserved for live steamers, it's called Spur II, Spur 2 in Germany.
Gauge 3 and Gauge 1 can often be called G scale which is technically incorrect G scale is a mish mash of mixed up loco and track scales, below.
G scale is basically any scale you like but running on 45m track, thus gauge 1 locos built to 1:32 can be correctly classed as G scale, by the same token a Harz 1m gauge loco built to 1:22.5 scale and running on 45mm track can also be called G scale. The only common factor in G scale is the track gauge at 45mm, everything else is flexible.
Where it all goes to pot is with LGB (Large Garden Bahn) they initially started out modeling 1m gauge trains, they opted for Gauge 3 which is 1:22.5 scale and luckily 1m gauge turns out to be 45mm wide so they use Gauge 1 track, though the rail is deeper and the sleeper spacings wider. That's all good and well if you are modeling 1mnarrow gauge railways but then LGB started producing main line locos, V160, V200, DR V100, Taurus etc, these are modeled at 1:22.5 scale, I.E Gauge 3 but run on 45mm track.
So in simple terms LGB main line loco bodys are the correct scale but the bogies have been compressed to 1m track gauge, to correct this you need to widen the bogie sideframes and wheels to 63.5mm track.....and build most of your own track too. I have looked at bot the V160 and V200 with a view to doing that as I primarily intend to static display them and super detail them accordingly, rather than run them in the garden but have also considered some 2½" gauge track as well.
HTH