High Speed Two (HS2) Colne Valley Viaduct

High Speed 2 (HS2) is a new high-speed railway connecting London and Birmingham (Phase 1). The ambitious project to add capacity to the UK rail network brings significant environmental and technical challenges. Chief among these is the Colne Valley Viaduct which crosses through beautiful countryside comprising lakes and woodland to the west of London. The 3.4km-long viaduct was described as the “most significant visible engineering feature of HS2 Phase 1” by the British Parliament.

Knight Architects’ concept design was inspired by the flight of a stone skipping across the water with a series of elegant open water spans, using distinctive V-shaped piers and an arched soffit. The site-specific typology continues with shorter spans set low into the landscape in wooded areas. This design was chosen to enable views across the landscape, minimise the viaduct’s footprint on the lakes, and help complement views across the natural surroundings.

The concept was developed into a Specimen Design with HS2 Phase 1 EDP, with Knight Architects leading extensive stakeholder engagement with the Colne Valley Regional Park Panel, formed from the multiple statutory and public bodies with interests in the project. Following award of the C1 construction contract to Align JV, the design of the viaduct was undertaken by Rendel Jacobs as Designer with Grimshaw as Architect.