Overview

• HS2 released new images on September 10 to confirm completion of the Colne Valley Viaduct, built by contractor Align JV.
• The bridge measures 2.1 miles and consists of 1,000 precast deck segments, with the final segment installed in September 2024 after work began in March 2021.
• The viaduct spans roads, lakes, the River Colne and the Grand Union Canal near Denham, linking London’s Hillingdon tunnels with the Chilterns.
• Finishing works since the last segment included parapet sections, noise barriers, waterproofing, drainage and a structural health monitoring system.
• When operational, HS2 trains are planned to cross the structure at speeds of up to 200 mph.