scale

G scale is 1:22.5

I found this during a simple web search for "model railroad scales" 

http://www.mendorailhistory.org/blog/wp-content/uploads/2011/11/scale-conversion-chart.jpg

are you trying to make something run or move?? if not there are 1/35 trains out now. although you might get a G train cheeper then a 1/35 scale kit :) or not good luck on your search

Clay

That would be I or 1 scale; at 1:32, at least at "standard" gauge, not sure what would be the best track scale for narrow gauge.  

That latter is middling important as narrow gauge (either 42" or 24") was often the first one installed in military situations.  (With the rather handy effect of being able to standardize existing rail beds by adding a rail at the narrower gauge.)