sorry if you get this twice but I sent it to the
other 7mm group first by mistake, its a bit confusing having two groups for the
I can't find a comparison chart for you but if my memory serves me correctly the
way to read this type of scale description is as follows .
first letter or figure designates the scale
"n" designates or stands for Narrow gauge
final figure represents the track gauge ( full size )
for example On3 equates to O
scale narrow gauge 3ft track gauge.
However there is a problem in this
in that while most of us think of O gauge as 7mm/ft it has to be remembered that
if the items concerned are American or intended for the American market they are
more likely to be 1/4"/ft and on a 3ft gauge line there is considerable
difference between the English 21mm gauge and the American 3/4" or
Whilst on the subject does anyone know where I can find more information on this
American scale as I am interested in the Irish narrow gauge but there obviously
problems with 21mm gauge and On3 might be my answer.