OO gauge
Encyclopedia
OO gauge or OO scale model railways are the most popular standard-gauge model railway tracks in the U.K. This track gauge is one of several 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...

 standards (4 mm:foot / 304.8 mm or 1:76.2) used, but it is the only one to be served by the major manufacturers. Despite this, the OO track gauge of is inaccurate for 4mm scale, and other gauges of the same scale have arisen to better serve the desires of some modellers for greater scale accuracy.

Origin

Double-0 scale model railways were launched by Bing
Bing (company)
Bing or Gebrüder Bing was a German toy company founded in 1863 in Nuremberg, Germany by two brothers, Ignaz and Adolf Bing, originally producing metal kitchen utensils.-History:...

 in 1921 as 'The Table Railway', running on track and scaled at 4mm to the foot. In 1922, the first models of British prototypes appeared. Initially all locomotives were powered by clockwork, but the first electric power appeared in autumn 1923.
OO describes models with a scale of 4mm = 1 foot (1:76) running on HO scale 1:87 (3.5mm = 1 foot) track (16.5mm/0.650"). This combination came about as early clockwork mechanisms and electric motors were difficult to fit within HO scale models of British prototypes which are smaller than equivalent European and US locomotives. A quick and cheap solution was to enlarge the scale of the model to 4mm to the foot but keep the 3.5mm to the foot gauge track. This also allowed more space to model the external valve gear. The resulting HO track gauge of 16.5mm represents 4 feet 1.5 inches at 4mm to the foot scale, this is 7 inches under scale or is approximately 2.33mm too narrow.

In 1932 the Bing company collapsed, but the Table Railway continued to be manufactured by the new Trix
Trix (company)
Trix is a German company that originally made Trix metal construction sets. In 1935 it began producing the electrically powered model trains that it became famous for, under the Trix Express label...

 company. Trix decided to use the new HO standard, being approximately half of European O gauge (1:43 scale).

In 1938, the Meccano
Meccano Ltd
Meccano Ltd was a British toy company established in 1908 by Frank Hornby in England to manufacture and distribute Meccano and other model toys and kits created by the company...

 Company launched a new range of OO models under the trade name of Hornby Dublo, OO gauge has remained the UK's most popular scale/gauge ever since.

In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, Lionel Corporation introduced a range of OO models in 1938. Soon other companies followed but it did not prove popular and remained on the market only until 1942. OO gauge was quickly eclipsed by HO scale. The Lionel range of OO used 19mm/¾" track gauge, a scale 57", a track width that was more to scale. There is a small following of American OO scale/gauge today.

Scaling

gauge at 4 mm:1-foot means that the scale gauge represents 4 foot, 7 inches (178 mm) narrower than the prototype . This noticeable difference are aggravated if over-scale rail section, over-scale wheel width and deep wheel flanges are used on typical models. These departures from scale require much larger clearances on pointwork
Turnout
Turnout may refer to:* Turnout , a rotation of the leg which comes from the hips, causing the knee and foot to turn outward, away from the center of the body* Turnout , a British film...

 and are particularly noticeable when looking along the track. This scale gauge more accurately represents the narrow gauge railways built to gauge, for example the Padarn Railway
Padarn Railway
The Padarn Railway was a narrow gauge railway line in Wales, built to the unusual gauge of . It was built to carry slate from the Dinorwic Quarry to Port Dinorwic. It opened in 1842, replacing the previous Dinorwic Railway. The Padarn Railway closed in 1961 .An unusual feature of the railway were...

 and Saundersfoot Railway
Saundersfoot Railway
The Saundersfoot Railway was a Welsh industrial narrow gauge railway built in 1829 to carry coal from mines around Reynalton to the harbour at Saundersfoot on the Pembrokeshire coast. It was the first railway line to be built in Pembrokeshire, remaining independent until it closed in 1939...

 in Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

 and the Glasgow Subway
Glasgow Subway
The Glasgow Subway is an underground metro line in Glasgow, Scotland. Opened on 14 December 1896, it is the third-oldest underground metro system in the world after the London Underground and the Budapest Metro. Formerly a cable railway, the Subway was later electrified, but its twin circular lines...

 in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

.

Though they run on the same track, OO gauge and HO gauge models of the same prototype do not sit well together since the OO models are larger than the HO equivalent.

OO is also used to represent the Irish gauge, where it is a scale 13+1/2 in too narrow.

These differences have led to the development of the finescale standards EM gauge
EM gauge
EM gauge is a variant of 4 mm to a foot scale used in model railways....

 and P4 scale.

OO today

OO remains the most popular scale for railway modelling in the United Kingdom; this is most likely attributable to a ready availability of ready-to-run stock and starter sets. Ready-to-run in the UK is dominated by Hornby Railways
Hornby Railways
Hornby Railways is the leading brand of model railway in the United Kingdom. Its roots date back to 1901, when founder Frank Hornby received a patent for his Meccano construction toy. The first clockwork train was produced in 1920. In 1938, Hornby launched its first 00 gauge train...

 and Bachmann Branchline
Bachmann Branchline
Bachmann Branchline is a brand name of Bachmann Industries used for British outline 00 gauge model railways.Bachmann, a US company founded in 1835, was purchased by Kader Industries in 1987. Kader had previously produced models for Palitoy under the 'Mainline' brand...

. Other sources of ready-to-run rolling stock or locomotives include the Dapol
Dapol
Dapol Ltd is a Welsh model railway manufacturer based in Chirk, Wales. The factory where design and manufacturing take place is just over the border in England.The Dapol trading name is known for its model railway products in N and OO gauges.-History:...

, Heljan
Heljan
Heljan A/S is a Danish model railway company based in Søndersø. Originally specialising in decorations and accessories for model railways, it has now also developed a substantial range of rolling stock. It has diversified into modelling the British scene, and since 2002 have released several OO...

, 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...

, ViTrains and previously Lima. Other scales, with the possible exception of N gauge, lack the variety and affordability of UK ready-to-run products, it is likely that this deters British modellers and leads to the prevalence of OO.

Good results in OO can be achieved despite the scale inaccuracies with modern ready-to-run equipment on ballasted Code 75 trackwork, with realistic track spacing (the "6-foot"), and try to minimise or hide tight curves where necessary.

4 mm finescale standards

Many experienced modellers find the OO standard produces a "narrow gauge" appearance when the model is viewed from head on. Greater accuracy is possible using either EM gauge
EM gauge
EM gauge is a variant of 4 mm to a foot scale used in model railways....

 or the closer to exact scale P4 gauge
P4 gauge
P4 or Protofour is a set of standards for model railways allowing a more accurate construction of models to a scale of 4 mm to 1 foot , the predominant scale of model railways of the British prototype...

 track.

Whilst flextrack is available for both EM and P4 gauges (from manufacturers such as C&L Finescale, SMP and The P4 Track Company), ready-to-run (RTR) point and crossing (P&C) work is not available, so this trackwork must be constructed by the modeller. Kits for doing this are also available from the aforementioned sources amongst others. Several of these kits are also available for the OO modeller who aims for more realistic track, since most RTR track is actually scaled to HO and does not represent any British prototype and the sleeper spacing is too close together for scale. EM gauge has slightly overscale flanges and flangeways on point and crossing work; P4 is closer to scale but the smaller flanges and flangeways on P&C work expose poor track construction.

Related scales

  • 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...

     - Used for modelling narrow gauge railways in 4 mm scale
  • OOn3
    OOn3
    OOn3 is a model railway standard for modelling narrow gauge railways in 4mm scale scale with gauge track. prototypes were common in Ireland and the Isle of Man, but the scale is not generally used outside the British Isles. gauge track is the same as that used in TT scale and HOm, so some...

     - Used for modelling narrow gauge railways in 4 mm scale
  • H0 - 3.5 mm scale using the same gauge track as 00.
  • EM
    EM gauge
    EM gauge is a variant of 4 mm to a foot scale used in model railways....

     - 4 mm scale using track.
  • P4
    P4 gauge
    P4 or Protofour is a set of standards for model railways allowing a more accurate construction of models to a scale of 4 mm to 1 foot , the predominant scale of model railways of the British prototype...

     - A set of standards using gauge track (accurate scale standard gauge track).
  • 00-SF - Uses track with ordinary 00 wheelsets. Allows the tighter trackwork tolerances of EM without the need to re-gauge wheels.

Manufacturers

  • Kitmaster - Manufactured plastic model kits of railway engines, rolling stock, and buildings.
  • Airfix
    Airfix
    Airfix is a UK manufacturer of plastic scale model kits of aircraft and other subjects. In Britain, the name Airfix is synonymous with the hobby, a plastic model of this type is often simply referred to as "an airfix kit" even if made by another manufacturer....

     - Bought the Kitmaster range and sold it under the Airfix brand until the original Airfix company collapsed in 1981. Some of the tooling was then destroyed, but Dapol (qv) bought the remainder. Most Airfix military vehicles are also to 1:76 scale.
  • Bachmann Branchline
    Bachmann Branchline
    Bachmann Branchline is a brand name of Bachmann Industries used for British outline 00 gauge model railways.Bachmann, a US company founded in 1835, was purchased by Kader Industries in 1987. Kader had previously produced models for Palitoy under the 'Mainline' brand...

     - One of the largest manufactures of ready to run 00.
  • Dapol
    Dapol
    Dapol Ltd is a Welsh model railway manufacturer based in Chirk, Wales. The factory where design and manufacturing take place is just over the border in England.The Dapol trading name is known for its model railway products in N and OO gauges.-History:...

     - Produce kits and ready to run wagons.
  • Heljan
    Heljan
    Heljan A/S is a Danish model railway company based in Søndersø. Originally specialising in decorations and accessories for model railways, it has now also developed a substantial range of rolling stock. It has diversified into modelling the British scene, and since 2002 have released several OO...

      - Produce a small number of locomotives and wagons.
  • Hornby Railways
    Hornby Railways
    Hornby Railways is the leading brand of model railway in the United Kingdom. Its roots date back to 1901, when founder Frank Hornby received a patent for his Meccano construction toy. The first clockwork train was produced in 1920. In 1938, Hornby launched its first 00 gauge train...

     - One of the largest manufacturers of ready to run 00.
  • Lima
    Lima (models)
    Lima S.p.A was a brand of railway models made in Vicenza, Italy, for almost 50 years, from the early 1950s until the company ceased trading in 2004...

     - Produced budget 00 ready to run, bought by Hornby.
  • Peco - Produce a wide range of track.
  • Willets Scale Models, Produce hand-made, brass, carriages and wagons.

External links

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