Construction progress of Britain's longest rail bridge

Building work continues after Colne Valley viaduct passes halfway point in Autumn 2023. The HS2's longest viaduct when complete it will span 3.4 km across the Colne Valley on London's north western edge. Engineered to carry trains speeding between HS2's London and Chiltern Hills tunnels at up to 320 km/h, the landmark structure will also be crowned Britain's new longest rail bridge.