High Speed Two (HS2) Phase 1 EDP Colne Valley Viaduct Specimen Design

High Speed 2 (HS2) is a new high-speed railway linking London with the Midlands (Phase 1) and Northern cities including Manchester (Phases 2a).

The ambitious project brings significant environmental and technical challenges. Chief among these in Phase 1 is the Colne Valley Viaduct which crosses through beautiful countryside to the west of London. Indeed, the 3.4km-long viaduct was described as the “most significant visible engineering feature of HS2 Phase 1” by British Parliament.

Knight Architects’ Specimen Design employed an innovative half-through deck that maximised soffit height to ground level and used the superstructure to mitigate against wheel-generated noise. The deck supports followed a site-specific typology of short 50m spans in wooded areas and longer 105m spans, using distinctive V-shaped piers and an arched soffit, when spanning over open water.

The viaduct design included a bespoke edge protection system, providing a transparent noise barrier, a guard against trains impacting wildlife and a safety parapet.

Knight Architects was appointed to develop a Specimen Design with HS2 Phase 1 EDP for the viaduct to demonstrate the art of the possible and to lead stakeholder consultation between HS2 and the multiple statutory and public bodies with interests in the project. The detailed design of the viaduct is being undertaken by the Align JV for HS2.