Great century

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, during the second decade of the 21st century, overlap each other. 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. 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 (IEP), 21 electric Class 800 trains were ordered as replacements for the ageing InterCity 125 diesels. In May 2016, owing to delays in the modernisation project, it was confirmed that the new trains would be converted to 'bi-mode', meaning they can run on diesel fuel and electric overhead wire.