Civil engineering work on HS2‘s Colne Valley viaduct, the UK’s new longest rail bridge, has been completed. The 2.1-mile-long structure, which will carry the new high-speed railway, surpasses the Tay Bridge to claim the record.
The viaduct crosses a series of roads, lakes, the River Colne, and the Grand Union Canal northwest of London. Its gentle curve is formed of 1,000 uniquely-shaped deck segments, on which trains will eventually operate at speeds of 200mph.
Construction, led by the Align joint venture (a partnership between Bouygues Travaux Publics, VolkerFitzpatrick, and Sir Robert McAlpine), began in March 2021. The final deck segment was put in place in September 2024. Finishing touches, including the installation of noise barriers, a structural health monitoring system, and waterproofing, have now been completed.
A “Stunning Feat of Engineering”
The viaduct marks a significant milestone for the HS2 project. Billy Ahluwalia, HS2 Ltd’s senior project manager for the viaduct, said: “The completion of the viaduct marks more than 10 years of planning, design and construction. I’m immensely proud of the level of dedication and professionalism shown by the whole team to maintain high standards of safety and quality, working over land and water to deliver. It’s a remarkable achievement. The viaduct is a structure of international significance – a stunning feat of engineering that will no doubt stand the test of time.”
Coralie Peroux, Align JV project director, said: “I’m immensely proud of the Align team and our supply chain partners, not just for successfully completing the UK’s longest rail bridge, but for the remarkable way they delivered it. Faced with the technical challenges in design and construction, they harnessed their expertise, worked as an integrated project team, and embraced collaboration. Their efforts have produced a striking HS2 landmark and created a valuable learning legacy for future designers, engineers and construction professionals.”
The structure is the longest of more than 50 major viaducts being built for HS2. It is situated between the 8.4-mile Northolt Tunnel and the 10-mile Chiltern Tunnel.
HS2 services will eventually run on dedicated tracks between London and Birmingham before continuing on the existing rail network to destinations further north.
