Britain’s gets new longest rail bridge in major HS2 milestone

Credit: HS2

HS2 has announced that the Colne Valley Viaduct, part of the HS2 high-speed rail project, has officially become the longest rail bridge in Britain following the successful installation of its final deck segment. Stretching 3.4km (2.1 miles) across the Colne Valley near Denham, the new structure surpasses the Tay Bridge, which had held the record since 1887.

Construction of the viaduct’s deck began in May 2022. Over the past 28 months, a team of engineers utilised a massive launching girder to position 1,000 pre-cast segments into place. The deck segments, each uniquely shaped to accommodate the structure’s curve, were produced on-site at a purpose-built factory. The balanced-cantilever method allowed for precise placement of the segments, creating an arch-supported structure across the 56 piers.

The viaduct will support HS2 trains traveling at speeds of up to 320 km/h (200 mph), linking London with Birmingham. It is one of 500 bridging structures planned for the HS2 project, which also includes footbridges, drainage culverts and ‘green bridges’ designed to support local wildlife.

Once the main civil engineering phase is complete, the factory and surrounding buildings will be dismantled. The area will be redeveloped into chalk grassland and woodland as part of HS2’s ‘green corridor’ initiative.

Billy Ahluwalia, Senior Project Manager at HS2 Ltd, said: “Lowering the Colne Valley viaduct’s final deck segment into place today marks the culmination of more than 10 years of planning, design and construction. I pay tribute to the dedicated team that has delivered a bridge that is both the longest on HS2 and has become the United Kingdom’s longest railway bridge.”

The completion of the viaduct comes shortly after the finish of HS2’s first major viaduct at Highfurlong Brook in Northamptonshire. Current efforts are focused on other critical components of the HS2 project, including the Delta Junction viaducts and the elevated approaches to Curzon Street station. The new rail line is expected to become operational between 2029 and 2033, promising faster, more reliable travel between major UK cities and easing congestion on existing rail networks.