In the 2010s Network Rail modernised the Great Western Main Line, the South Wales Main Line, and other associated lines. The modernisation plans were announced at separate times but their implementation overlapped in the 2010s.
The work included electrification, resignalling, new rolling stock and station upgrades. The programme began in June 2010 and at that time was due to end in 2017.[1] The project was completed in 2020, allowing electric services to run between London Paddington and Cardiff.[2]
The project had several delays.[3] Four sections were deferred indefinitely:[3][4]
The Cardiff to Swansea electrification was cancelled in 2017.[7]
Under the Intercity Express Programme (IEP), 21 electric Class 801 trains were ordered as replacements for the ageing InterCity 125 diesels. In May 2016 it was confirmed that the new trains would be built as 'bi-mode' Class 800s instead, meaning they can run on either diesel power or electric overhead wire.[8]
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