Passengers are advised to plan ahead as Network Rail carry out major upgrade in the Severn Tunnel and Bristol area, with replacement buses and diversionary routes in place to keep people moving from late May to early June.

This vital project will see Network Rail, and contractors ARQ, complete the transformation of the Severn Tunnel’s overhead power system, designed specifically to withstand the tunnel’s harsh, corrosive environment - making it more resilient, reducing the frequency of maintenance, and helping to minimise disruption for passengers.

The work will take place around the clock from Saturday, May 23 until the early hours of Tuesday, June 9, with the railway closed between Newport and Bristol Parkway during this time.

Running beneath the Severn Estuary, the 4.35-mile Severn Tunnel is one of the toughest environments on the UK rail network, where moisture and saltwater accelerate wear on equipment.

Since electrification, the overhead power system has been prone to corrosion and electrical wear, leading to more frequent maintenance.

To address this, Network Rail’s Wales and Borders team has developed and successfully trialled an innovative new system. It uses a single 7km copper contact wire supported at regular intervals by modified bridge arms, to eliminate previous corrosion issues and improve performance.

Engineers will now install this system along the full length of the tunnel - using a world-first approach on this scale - to create a more resilient railway and reduce the need for frequent maintenance.

The programme of work involves:

Alongside the tunnel work, Network Rail will also carry out improvements in the Bristol area, including upgrades to the railway serving the new Bristol Brabazon station on the former Filton airfield site. The station is due to open in the autumn and will bring passenger services back to the Henbury line for the first time since 1964.

Passengers are advised to check before they travel and allow extra time for their journeys.

Marcus Deegan, GWR's Station Manager at Bristol Parkway, said: “We know that bus replacement services are a significant ask of passengers, and we're genuinely grateful for their patience while this vital work is completed.

“This investment to improve and maintain the Severn Tunnel will make a real difference to the reliability and resilience of the route for many years ahead.

“Our team at Bristol Parkway is on hand to help customers navigate their options, and we've worked hard to put in place replacement services that keep people moving. The most important thing anyone can do is check their journey in advance at GWR.com and allow a little extra time.”