On30 gauge

On30 (also called On21⁄2, O16.5 and Oe) gauge is the modelling of narrow gauge railways in O scale on HO (16.5 mm / 0.65 in) gauge track in 1:48 scale ratio by American and Australian model railroaders, in 1:43.5 scale ratio by British and French model railroaders and 1:45 by Continental European model railroaders (excluding France).

On30 uses the American O scale of 1⁄4 inch to the foot, (ratio 1:48) to operate trains on HO gauge (16.5 mm / 0.65 in) track. The 30 indicates the scale/gauge combination is used to model 2 ft 6 in (762 mm) narrow gauge prototypes, although it is often used to model 2 ft (610 mm) and 3 ft (914 mm) gauge prototypes as well. This scale/gauge combination is sometimes referred to as On21⁄2.

O16.5 (sometimes O-16.5) in the United Kingdom is a model railway scale/gauge combination of 7 mm to the foot. This is the same scale as British O scale (1:43.5 ratio) running on 16.5 mm (0.65 in) gauge track, which is also used by OO gauge model railways. It thus represents the prototype gauge of just over 2 ft 4 in (711 mm) (e.g. the Snailbeach District Railways), although also widely used to model 2 ft (610 mm) (e.g. the Ffestiniog Railway) and 2 ft 3 in (686 mm) (e.g. the Tal-y-llyn Railway) gauge UK prototypes.

0e (sometimes Oe) is the Continental European notation for 0 scale using 16.5 mm (0.65 in) track. In France and a few other countries 0 scale uses a ratio of 1:43.5. In Germany and many other European countries 0 scale uses a ratio of 1:45. The prototypes represented as example the German 750 mm (2 ft 5+1⁄2 in) gauge, Austrian 760 mm (2 ft 5+15⁄16 in) gauge, and 800 mm (2 ft 7+1⁄2 in) gauge rack railways in Switzerland.

In the United States modelling in On30 dates back to the 1950s, using HO gauge wheels and locomotive chassis. The scale was popularised to some extent in the 1960s and 1970s by the writings of modellers such as Gordon North. An On30 layout, the Venago Valley (built by Bill Livingston) was featured in the June 1971 issue of Railroad Model Craftsman magazine. However, as there are very few prototype 2 ft 6 in (762 mm) gauge railways in the United States, it remained very much a minority modelling area, especially when compared with modelling in On2 and On3.

In 1998 Bachmann Industries introduced a model of a 2-6-0 steam locomotive in this scale for the Christmas village market. This model, being very inexpensive, was quickly adopted by modellers. Other manufacturers followed Bachmann into this market, and Bachmann also introduced a number of other models. On30 is now regarded as the fastest growing segment of the model railroading market in the United States.^{[citation needed]}

Several other companies have produced mass market models for the USA market including Mountain Model Imports (MMI) who produced die-cast K series DRGW models (also available in 0n3), Broadway Limited who produced a 2-8-0 and a "galloping goose", San Juan Car company produce kits and RTR plastic wagons, Accucraft/AMS produce brass engines and plastic rolling stock.

Many US modellers can be broadly cast into one of two groups:^{[citation needed]}