HS2 Completes Full Construction of Britain’s Longest Rail Bridge

HS2 has announced the completion of civil engineering works on the Colne Valley viaduct, the longest rail bridge in the UK.

The 2.1-mile-long structure, which is one of fifty new viaducts being built as part of the HS2 project, will carry passengers over roads, lakes, the River Colne and the Grand Union Canal at 200mph.

Construction of the viaduct first began in March 2021, and was carried out by Align, a joint venture between Bouygues Travaux Publics, VolkerFitzpatrick and Sir Robert McAlpine, HS2’s main works contractor for this section of the route.

Work was completed with the placement of the final pre-cast deck segments in September 2024, with the last 12 months seeing Align install parapet sections, noise barriers, a structural health monitoring system and waterproofing & drainage.

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.

HS2 is now undergoing a ‘comprehensive reset’ in order for the project to be delivered ‘in the most efficient way possible and for the lowest reasonable cost’.

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.