Modelling 3' gauge railroads

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Modelling 3' gauge railroads is part of the hobby of rail transport modelling. Specifically it relates to the modelling of narrow gauge prototypes of 3' (914mm) gauge. This gauge was the most common narrow gauge in the United States and in Ireland. Apart from some other lines in North and Central America, 3' gauge was uncommon elsewhere. Therefore most 3' gauge modellers model either United States or Irish prototypes.

[edit] United States

3' gauge railroads were widespread in the United States in the period 1880-90. While most of these railroads were converted to standard gauge by the start of the 20th Century, a number of lines survived till the Second World War and later, and became popular subjects for modelling.

Probably the most popular prototype is the Denver and Rio Grande Western Railroad, followed by other Colorado railroads such as the Rio Grande Southern and Colorado and Southern. Other railroads from California and the eastern states are also popular.

Scale and gauge combinations used in modelling include:

Nn3 - Using N scale (1:160 ratio ) with Z (6.5mm) gauge track. This is the smallest commercial scale.
HOn3 - Using HO scale (1:87 ratio} with 10.5mm gauge track. Historically the most popular of the scale/gauge combinations.
Sn3 - Using S scale (1:64 ratio) with 14.3mm gauge track. Limited commercial support.
On3 - Using O scale (1:48 ratio) with 19.05mm gauge track. Probably the second most popular scale.
F scale - using 1:20.3 ratio with 45mm gauge track. This scale uses the same gauge as, and is derived from the popular G scale. It is the largest popular scale/gauge combination, and is suitable for use in the garden.

3' gauge models can be modelled on other gauge track. The growth of On30, where 3' prototypes are often modelled on 16.5mm gauge track, has made this increasingly popular. While purists dislike this trend, the influx of new modellers has provided cheaper models and increased choice to the On3 modeller.

Perhaps not surprisingly, most narrow gauge modellers in the United States model US 3' gauge prototypes. However these prototypes are also popular modelling subjects outside the United States as well.

[edit] Ireland, the Isle of Man, and Britain

3' gauge was the narrow gauge used in Ireland, and the gauge of the railway on the Isle of Man. It was also used on a handful of railways in Britain. However modelling these 3' gauge railways is very much a minority pursuit, especially when compared with other prototypes such as the Welsh narrow gauge. Scales and gauges used include:

3mm to the foot scale (1:101 ratio), modelling on 9mm or N gauge track.
4mm to the foot scale (1:76 ratio, orOO scale), modelling on 12mm gauge track (OO3).
5.5mm to the foot scale (1:56 ratio), modelling on 16.5mm or HO/OO gauge track.
7mm to the foot scale (1:43.5 ratio, or O scale), modelling on 21mm gauge track.
15mm to the foot scale (1:20.3 ratio), modelling on 45mm gauge (G scale) track.

None of these scale/gauge combinations has much commercial support, and therefore modellers are required to construct most of their models from scrach.