Colne Valley Viaduct

Colne Valley Viaduct
Artist's depiction of the completed viaduct
Coordinates	51°35′09″N 0°29′24″W / 51.5859°N 0.4900°W / 51.5859; -0.4900
Carries	High Speed 2
Crosses	Colne Valley Regional Park
Locale	Harefield
Owner	Align MWCC
Characteristics
Total length	2.1 miles (3.4 km)[1]
Height	10 metres (33 ft)[1]
Rail characteristics
No. of tracks	2
Track gauge	1,435 mm (4 ft 8+1⁄2 in)
Electrified	25 kV 50 Hz AC
History
Architect	Align MWCC
Construction start	March 2021
Construction end	Under construction
Statistics
Daily traffic	High speed passenger trains
Location

The Colne Valley Viaduct is a bridge, under construction as of 2024, which will carry the High Speed 2 railway over the Colne Valley Regional Park and the Grand Union Canal, in Hillingdon, west London. When completed, its length of 3.4 kilometres (2.1 mi) and a weight of 116,000 tonnes will make it the largest railway bridge in the UK. It is one of the largest single civil engineering works of HS2 Phase 1.^[2]

A contract for the section of the railway pertaining to the viaduct was awarded during 2017 and the design concept was released to the public on 19 January 2018. Preparatory work commenced shortly thereafter, including a compulsory land purchase and the establishment of temporary facilities, including a factory, onsite. Construction of the viaduct commenced during March 2021 with the main deck completed in September 2024 with full completion expected for May 2025.^[3][4] Protestors have occasionally occupied the site, and allegations over the viaduct's aesthetic and environmental impact upon the area have been made.