page_title: OO gauge
section_title: Origin
hierarchical_section_title: OO gauge / Origin
caption_attribution_description: A OO-gauge Flying Scotsman
context_page_description: OO gauge or OO scale is the most popular standard-gauge model railway standard in the United Kingdom despite being virtually unknown in other countries. This track gauge is one of several 4 mm-scale standards used, but it is the only one to be served by the major manufacturers. Unfortunately, the OO track gauge of 16.5 mm is actually incorrect for 4 mm scale, giving a track gauge equivalent of 4 ft 1½ in instead of 4 ft 8½ in. However, since the 1960s, other gauges in the same scale have arisen to reflect the desire of some modellers for greater scale accuracy.
context_section_description: Double-0 scale model railways were launched by Bing in 1921 as "The Table Railway", running on 16.5 mm (0.65 in) track and scaled at 4 mm-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 4 mm = 1 foot (1:76) running on HO scale 1:87 (3.5 mm = 1 foot) track (16.5 mm/0.650"). This combination came about as early clockwork mechanisms and electric motors were difficult to fit within HO scale models of British trains which are smaller than European and North American counterparts. A quick and cheap solution was to enlarge the scale of the model to 4 mm-to-the-foot but keep the 3.5 mm-to-the-foot gauge track. This also allowed more space to model the external valve gear. The resulting HO track gauge of 16.5 mm represents 4 feet 1.5 inches at 4 mm-to-the-foot scale; this is 7 inches under scale, or approximately 2.33 mm too narrow.
  In 1932 the Bing company collapsed, but the Table Railway continued to be manufactured by the new Trix company. Trix decided to use the new HO standard, being approximately half of European 0 gauge (1:43 scale).
  In 1938, the Meccano 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, 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 19 mm/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.
caption: Hornby Railways Flying Scotsman locomotive on an 00 gauge layout
exif: {"Image Make": "FUJIFILM", "Image Model": "FinePix A330", "Image Orientation": "0", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Digital Camera FinePix A330    Ver1.77", "Image DateTime": "2006:01:06 17:01:22", "Image YCbCrPositioning": "Co-sited", "Image Copyright": "", "Image ExifOffset": "251", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1227", "Thumbnail JPEGInterchangeFormatLength": "5732", "EXIF ExposureTime": "1/60", "EXIF FNumber": "4", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2006:01:06 17:01:22", "EXIF DateTimeDigitized": "2006:01:06 17:01:22", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ShutterSpeedValue": "6", "EXIF ApertureValue": "4", "EXIF BrightnessValue": "-151/100", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash fired, auto mode", "EXIF FocalLength": "119/10", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "1024", "EXIF ExifImageLength": "768", "Interoperability InteroperabilityIndex": "", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "1103", "EXIF FocalPlaneXResolution": "2466", "EXIF FocalPlaneYResolution": "2466", "EXIF FocalPlaneResolutionUnit": "3", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0"}