Great Western Main Line Electrification Programme (GWEP)
London Paddington to west and south-west England and south Wales (Maidenhead to Oxford/Newbury/Bristol/Swansea), UK · 2011–2019 (main delivery period, some elements de-scoped/deferred) · £2.8bn (estimated cost, 2015 prices)
The judgement call
Account-gated at launchThe Hendy Review in late 2015 led to a reduced scope of electrification and delayed delivery for some capacity-led engineering components. - Decision to procure all bi-modal rolling stock instead of a mixed fleet of electric-only and bi-modal trains. - Significant cost increases and programme delays highlighted the challenges of major infrastructure upgrades.
Key engineering challenges
Integrating new electrification infrastructure with existing, operational railway lines, including complex overhead line equipment installation. - Managing significant scope changes and cost overruns, leading to de-scoping and deferral of some electrification sections. - Technical challenges associated with electrifying a historic route with numerous tunnels, bridges, and complex interfaces.
Project facts
- Client / owner
- Department for Transport (DfT), Network Rail
- Lead contractor
- Network Rail, Bechtel
- Lead designers
- Atkins
- Project type
- upgrade
- Scale
- Electrification of Great Western Main Line between Maidenhead and Oxford/Newbury/Bristol/Swansea; introduction of new Intercity Express Programme (IEP) bi-modal rolling stock; station improvements.
- Disciplines
- civil; electrical; systems; project management; environmental
- Standards & frameworks
- Network Rail standards, CDM Regulations
Sources: Great Western Route Modernisation First Post-Opening Evaluation – Final Report (April 2022, https://assets.publishing.service.gov.uk/media/649c5957bb13dc000cb2e2cb/great-western-route-modernisation-first-post-opening-evaluation-final-report.pdf); The Guardian (Oct 2015, https://www.theguardian.com/uk-news/2015/oct/21/cost-to-electrify-great-western-mainline-triples-to-28bn-risking-other-schemes); Parliament.uk (Mar 2017, https://committees.parliament.uk/committee/127/public-accounts-committee/news/98496/failings-on-great-western-upgrade-raise-concerns-over-future-rail-projects/)