Editing G scale (section)

==G scale versus G gauge==
{{Main|Rail transport modelling scales}}
G [[Track gauge|gauge]] track has a spacing of 45 mm between the rails, adopted from the pre-existing Gauge 1, but that does not determine the scale to which the models are built because, to maintain a constant track width when real-life counterparts have a variety of railroad gauges, the scale has to vary. The most common full-scale practice uses a spacing of {{RailGauge|ussg|allk=on}}, whereas some [[narrow-gauge railway]]s (serving mines, etc.) have rails only {{RailGauge|36"}} apart. Although often built with standard-sized doors, a narrow-gauge train is in most other respects smaller than its standard-gauge counterpart: its cars are generally narrower and shorter, allowing them to navigate more sharply curved and lightly built tracks.

Model trains are built to represent a real train of standard or narrow gauge.  For example, [[HO scale]] (1:87 or 3.5&nbsp;mm to 1 foot) (and also, although inaccurately, [[OO gauge|double-O/OO]] at 4&nbsp;mm to 1 foot) models all use 16.5&nbsp;mm gauge track to represent [[standard gauge]] trains while a narrower-gauge track such as 9&nbsp;mm N gauge is used to represent real narrow gauge. 

G model railways depart from this and always use the same gauge with the trains instead built in different sizes depending on whether they are intended to represent standard-gauge or narrow-gauge trains. Because of this it might be more correct to speak of "G gauge" rather than "G scale" since the consistent aspect is the gauge, {{RailGauge|45 mm}}, but the term "G scale" (or "scale IIm") is used when 1:22.5 is used.

The 45&nbsp;mm gauge originated from [[1 gauge]] or "gauge one" which was first used in Europe and Britain and used to model standard gauge trains in the scale of 1:32.

[[LGB (trains)|LGB]] were first to adopt the term ''G scale'' and used the gauge of {{RailGauge|45 mm}} to model 1,000&nbsp;mm gauge European trains in 1:22.5 scale.  

=== Scales that run on G gauge track ===
* 1 gauge: 1:32 ({{frac|3|8}} inch to the foot). Used to model standard gauge trains of {{RailGauge|4'8.5"|allk=on}} gauge.
* 1:29 scale or A scale: 1:29. First used by Aristo-Craft to model standard-gauge prototypes. Incorrect scale/gauge but proportionally similar to other popular brands of the time.
* G scale: 1:22.5. Used to model European trains that run on {{RailGauge|1,000 mm}} [[metre gauge]] track. This scale-gauge combination is called "scale IIm" according to [[Normen Europäischer Modellbahnen|NEM]] 010. The ''G'' comes from the German word {{lang|de|groß}} meaning "big".
* H scale (half inch) {{frac|1|2}}-inch-to-the-foot, or 1:24 scale. Used to model {{RailGauge|3 ft 6 in}} gauge or "[[Cape gauge]]". Incorrect scale used for [[3 ft gauge railways|3&nbsp;ft (914&nbsp;mm) gauge]] track.
* F scale (fifteen) 15&nbsp;mm-to-the-foot scale, (1:20.32). Correct scale/gauge typically used to model North American narrow gauge trains on {{RailGauge|3ft}} gauge track.
* Seven eighths: {{frac|7|8}}-inch-to-the-foot scale (1:13.7). Used to model trains on {{RailGauge|2ft}} [[narrow gauge]] track.
* 16&nbsp;mm scale: 16&nbsp;mm-to-the-foot (1:19.05). Originally intended for modelling 2-ft gauge prototype railways on 32&nbsp;mm track (SM32). The models are often re-gauged to also run on 45&nbsp;mm track. This scale has also been used to model {{track gauge|2ft6in|lk=on}} gauge prototype trains.