OOn3 is a model railway standard for modelling narrow gauge railways in 4mm scale

4mm scale

4 mm scale is the most popular model railway scale used in the United Kingdom. The term refers to the use of 4 millimeters on the model equating to a distance of 1 foot on the prototype...

 scale with gauge track. prototypes were common in Ireland

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 and the Isle of Man

Isle of Man

The Isle of Man , otherwise known simply as Mann , is a self-governing British Crown Dependency, located in the Irish Sea between the islands of Great Britain and Ireland, within the British Isles. The head of state is Queen Elizabeth II, who holds the title of Lord of Mann. The Lord of Mann is...

, but the scale is not generally used outside the British Isles

British Isles

The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

. gauge track is the same as that used in TT scale

TT scale

thumb|right|250px|TT scale model railroadTT scale is a niche model railroading scale, whose name stands for Table Top.Its 1:120 scale and gauge sizes it almost halfway between HO scale and N scale...

 and HOm

HOM

HOM, HoM or HOm can refer to:*Hall of mirrors effect, in 3D computer graphics*Hands On Miami, a volunteer community-service organization in Miami, Florida*Heart of Misery, a song by Finnish rock band The Rasmus...

, so some components used for those scales can be used. There is no ready-to-run support, so everything must be built from scratch

Scratch building

Scratch building is the process of building a scale model "from scratch", ie. from raw materials, rather than building it from a commercial kit, kitbashing or buying it pre-assembled....

 or from kits supplied by Worsley Works

Worsley Works

Worsley Works, is a manufacturer of kits for model railway carriages and locomotives, owned and run from Worsley, UK, by Allen Doherty.Worsley Works is well-known in the finescale modelling world, especially in less-popular scales, including British HO scale and 3mm-scale models along with...

, Backwoods miniatures and Parkside Dundas amongst others. OOn3 modellers have close relations with other 4 mm narrow gauge modellers, especially OO9

OO9

OO9 is a model railway scale and gauge combination of 4 mm scale and gauge tracks, which models a prototype track gauge of . It is a common choice in the United Kingdom for the modelling of narrow gauge railways whose prototype gauges lie approximately between and...

 modelling.

Related Scales

Outside the British Isles

British Isles

The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

 the similar 1:87 scale is used. For European (metre gauge

Metre gauge

Metre gauge refers to narrow gauge railways and tramways with a track gauge of . In some African, American and Asian countries it is the main gauge. In Europe it has been used for local railways in France, Germany, and Belgium, most of which were closed down in mid 20th century. Only in Switzerland...

) prototypes and African / Australian gauge railways HOm

HOM

HOM, HoM or HOm can refer to:*Hall of mirrors effect, in 3D computer graphics*Hands On Miami, a volunteer community-service organization in Miami, Florida*Heart of Misery, a song by Finnish rock band The Rasmus...

 is used. In America gauge railroads are modelled on gauge track
as HOn3.

External links

• OO9 Society
• Backwoods Miniatures
• Peco
  Peco
  Peco is a UK-based manufacturer of model railway accessories, especially trackwork, based at Pecorama, Beer in South Devon.Peco is the collective name for the Pritchard Patent Product Company Ltd, Peco Publications and Publicity Ltd, and Pecorama...
  
   - HOm track
• Parkside Dundas - Also list other manufacturers kits
• Worsley Works
  Worsley Works
  Worsley Works, is a manufacturer of kits for model railway carriages and locomotives, owned and run from Worsley, UK, by Allen Doherty.Worsley Works is well-known in the finescale modelling world, especially in less-popular scales, including British HO scale and 3mm-scale models along with...
  
  - Rolling stock and Locomotive kits