The 2.1 mile-long structure carries the railway across a series of roads, lakes, the River Colne and the Grand Union Canal, north west of Hillingdon.
Trains will operate at 200mph on the viaduct’s gentle curve, which is formed of 1,000 uniquely-shaped deck segments.
Work on the 10 metre-tall viaduct started in March 2021 and the last of the giant segments was lowered into place in September 2024.
Since then, contractor Align has been putting the finishing touches to the new landmark.
This includes installing parapet sections, noise barriers, a structural health monitoring system, waterproofing and drainage.
It means the Tay Bridge, linking Fife and Dundee, has finally ceded the crown of Britain’s longest rail bridge, a record it had held since 1887.
Far more work is needed, however, to achieve the same level of completion elsewhere on the 140-mile route between London and the West Midlands.
Mark Wild, HS2 Ltd’s chief executive, has announced he is leading a reset to finish the project in the most efficient way, for the lowest reasonable cost.
Billy Ahluwalia, HS2 Ltd’s senior project manager for the viaduct, said: “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.”
You can also watch the video on https://youtu.be/UDs4hfE3anU
