page_title: 21st-century modernisation of the Great Western main line
section_title: Resignalling
hierarchical_section_title: 21st-century modernisation of the Great Western main line / Resignalling
caption_attribution_description: English: Signal B39 at the north end of platform 3 at Bristol Temple Meads station. In this photograph the three-aspect signal is displaying a caution aspect with a route indication of "UR" for the Up Relief line.
context_page_description: Network Rail plans to spend £5 billion on modernising the Great Western main line, its South Wales branch and other associated lines. The modernisation plans were announced at separate times but their development time-scales overlap in the 2010s. The work includes electrification, resignalling, new rolling stock and station upgrades. According to Network Rail, the modernisation started in June 2010 and was due to end in 2017. As of December 2019, electrification was complete as far west as Cardiff Central, and also from Reading to Newbury.
  The project has been subject to repeated delays. In November 2016 the government announced that several major elements of the electrification programme would be indefinitely deferred because costs had tripled. The five sections that are delayed are:
  Oxford to Didcot Parkway
  Bristol Parkway to Bristol Temple Meads
  Thingley Junction, near Chippenham, to Bath Spa and Bristol Temple Meads
  Thames Valley branches to Henley and Windsor
  Swansea to Cardiff.
  Under the Intercity Express Programme, 21 electric Class 800 trains were ordered as replacements for the ageing InterCity 125 diesels.
caption: Example of an existing colour light signal at Bristol Temple Meads station
exif: {"Image Make": "Panasonic", "Image Model": "DMC-FZ20", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Ver1.0", "Image DateTime": "2005:12:07 15:18:31", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "418", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 50, 53, 48, 0, 0, 14, 0, 1, 0, 22, 0, ... ]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail Orientation": "Horizontal (normal)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "6804", "Thumbnail JPEGInterchangeFormatLength": "4638", "Thumbnail YCbCrPositioning": "Co-sited", "EXIF ExposureTime": "1/60", "EXIF FNumber": "14/5", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "150", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2005:12:07 15:18:31", "EXIF DateTimeDigitized": "2005:12:07 15:18:31", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "72", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1600", "EXIF ExifImageLength": "1200", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "6652", "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 DigitalZoomRatio": "0", "EXIF FocalLengthIn35mmFilm": "432", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "Low gain up", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal"}