This special issue of Civil Engineering covers the Great Western railway electrification in the UK.

Completed in January 2020, this £3 billion programme of works involved threading overhead line equipment along 650 km of live railway tracks and through dozens of historic bridges and tunnels. It has enabled new quiet, efficient and reliable electric trains to run between London Paddington and Cardiff in South Wales, delivering significant environmental and service benefits.

The seven papers in this issue describe many of the challenges and lessons learned in delivering this huge programme – the first major electrification scheme in the UK for a generation.