What is G Scale ?       What is G Gauge ?


Words that might seem clear to some using a dictionary reference.

Words that might seem clear to many "model railroader"s.

But when you say "G scale" the understanding seems to get lost…


In short...


    G scale is  1/22.5  in ratio


    G gauge is  45mm  between the rails



Over 50 years ago, the German firm called Marklin started marketing model trains in a larger size and used three gauges to run them on.  The track sets were called  Gauge One,  Gauge Two  and Gauge Three.  These faded as many scales and gauges did back then did, mostly due to smaller scales becoming more popular (like the OO, or as we have in the US, HO scale/HO gauge). 


About 30 years ago, LGB of Germany picked the old “Gauge One” to start making a new size of trains, designed for outdoor garden running.  These were a larger durable size for children to easily play with.  They decided to model the smaller narrow gauge trains often found in quarries and branch lines that ran on “meter gauge” tracks.  To do this they found a scale ratio of  22 1/2  (or 22.5) to one, would model meter gauge track using the older Gauge One system.


This Gauge One track system was soon called “G Gauge”. 


While the source of the letter 'G' is debated, some old text found say its Gosh or Great scale.  When these larger trains came to the United States, the American modelers need to have a "letter" label stuck with the "G" and so we have what was dubbed “G Scale”. 


The large scale trains built in 1/22.5 scale are “G scale”.



Many in the United States wanted "American style" trains.  So LGB designed a limited series of American “narrow gauge” cars to run on their G gauge track.  These were designed around American 3 foot gauge equipment and were built in 1/22.5 scale.  These cars were not high detailed models but very nice quality, and accepted my many even though the “LGB track” was really meter gauge.


A couple US firms then proceeded to design American style trains to run on the existing "garden railroad" track systems...  on the existing "G gauge" tracks that people already had.  Many built engines and cars based on the common gauge we have in the US called "Standard Gauge" (which is 4 feet, 8 1/2 inch gauge in real size).


Since the most common track was G gauge by LGB, and in 1/22.5 scale this track was "meter gauge", these firms made up new scales.  These scales range from 1/32 and 1/29, to model the Standard Gauge size trains.  Some tried using a common “doll house” scale called “half inch scale” which is 1/24, to model American narrow gauge, to run on G gauge track. 


In more recent years, several firms have designed to step back and use a correct “scale to gauge” of 1/20.3, to model American 3 foot narrow gauge, again using the common LGB G gauge track that, so many have in their back yards.  Being a correct or fine scale, the letter label of “F” has been applied. 


Maybe the next common is 1/16 which is modeling American Two Foot gauge trains using  you guessed it,  LGB’s track gauge.  A handful of other scales are in use that run on



All these scales run on the "G gauge" track that Marklin first mass marketed over 50 years ago, and LGB brought back to life and made popular 30 years ago, as what we now call...  "G gauge".  An odd side note is when LGB went bankrupt in recent years, they were later bought by Marklin.


So today you find several odd scales that run on G gauge track.  The most popular other scale is 1/29, which has many manufactures building American "standard gauge" type trains to run on LGB's meter gauge track.  Plus the growing trend is the correct scale to gauge folks, that want correct American, narrow gauge, 3 Foot Gauge equipment to run on G gauge track, so model in 1/20.3 scale.


With the American letter labels of G and F, many of us call it "Gn3" when we use of 1/22.5 scale equipment running on the LGB track size, modeling American 3 foot, narrow gauge...  although it’s 39 1/2 inch gauge track when you scale it out.  This was the first efforts to model American narrow gauge.  Today the "Fn3" group which models correct scale to gauge, of  1/20.3  equipment running on the track that scales to 3ft gauge at 20.3 ratio.  Odd is vast number of folks running trains in 1/29 scale, which still today has no "letter label".



What is G scale  And what is G gauge?  If you understand the words,

if you are a model railroader, you know what scale and gauge means.


Thus...   G scale is 1/22.5 scale.  And G gauge is 45mm between the rails.


So Gn3 is modeling 3 foot gauge narrow gauge trains in 1/22.5 scale.

And there are various “scales” that run on the popular G gauge track.

Not all trains on LGB track are not “G scale” but they use G gauge…


            (  a similar trend in recent years has been using HO gauge track to run On30 trains  )

            (  thus 1/48 O scale trains, running on a track gauge used by 1/87 scale HO trains  )



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