page_title: Track gauge
section_title: Maintenance standards
hierarchical_section_title: Track gauge / Maintenance standards
caption_attribution_description: English: Two Network Rail engineers check the gauge of the track in the Park Sidings at Plymouth station.
context_page_description: In rail transport, track gauge or track gage is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails.
  All vehicles on a rail network must have running gear that is compatible with the track gauge, and in the earliest days of railways the selection of a proposed railway's gauge was a key issue. As the dominant parameter determining interoperability, it is still frequently used as a descriptor of a route or network.
  In some places there is a distinction between the nominal gauge and the actual gauge, due to divergence of track components from the nominal. Railway engineers use a device, like a caliper, to measure the actual gauge, and this device is also referred to as a track gauge.
  The terms structure gauge and loading gauge, both widely used, have little connection with track gauge. Both refer to two-dimensional cross-section profiles, surrounding the track and vehicles running on it. The structure gauge specifies the outline into which new or altered structures must not encroach. The loading gauge is the corresponding envelope within which rail vehicles and their loads must be contained.
context_section_description: Infrastructure owners specify permitted variances from the nominal gauge, and the required interventions when non-compliant gauge is detected. For example, the Federal Railroad Administration in the USA specifies that the actual gauge of a 1,435 mm track that is rated for a maximum of 60 mph (96.6 km/h) must be between 4 ft 8 in (1,422 mm) and 4 ft 9.5 in (1,460 mm).
caption: Engineers checking the gauge between rails at Plymouth (England)
exif: {"Image Make": "Canon", "Image Model": "Canon EOS 550D", "Image Orientation": "Horizontal (normal)", "Image DateTime": "2018:02:22 09:41:52", "Image Artist": "", "Image YCbCrPositioning": "Co-sited", "Image Copyright": "", "Image ExifOffset": "2236", "Image XPAuthor": "[0, 0]", "Image Padding": "[]", "EXIF ExposureTime": "1/400", "EXIF FNumber": "18", "EXIF ExposureProgram": "Shutter Priority", "EXIF ISOSpeedRatings": "1600", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2018:02:22 09:41:52", "EXIF DateTimeDigitized": "2018:02:22 09:41:52", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "69/8", "EXIF ApertureValue": "67/8", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "260", "EXIF SubSecTime": "87", "EXIF SubSecTimeOriginal": "87", "EXIF SubSecTimeDigitized": "87", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3456", "EXIF ExifImageLength": "2304", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "12568", "EXIF FocalPlaneXResolution": "691200/181", "EXIF FocalPlaneYResolution": "460800/119", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF Padding": "[]", "EXIF OffsetSchema": "4168"}