The four-mile long Severn Tunnel linking Bristol to South Wales is to close for six weeks from 12 September as part of work to electrify the Great Western main line between London and Cardiff.
Engineers will install conductor rail in the tunnel to provide power to the new Class 800 and 801 Hitachi Inter-city Express trains, which are due to be introduced on the route from 2017. Preparatory work currently underway includes the removal of soot from the tunnel and repairs to brick work.
During the closure, services between London and South Wales will be diverted between Swindon and Newport and will run via Gloucester, adding up to 40 minutes to the journey. Other local services will terminate at Bristol Parkway, where replacement buses will provide transport across the river into South Wales.
Paul McMahon, Network Rail’s route managing director for Wales, said: ‘Without a solid six-week closure, it would take engineers up to five years to complete the upgrade, causing long-term disruption for passengers and delaying the new electric trains until 2021’.
The revised schedule for Great Western electrification, revealed when Network Rail’s Enhancements Delivery Plan was updated in January, gives an indicative completion date for electrification between Bristol Parkway and Cardiff of December 2019, two years later than originally planned.