Colne Valley Viaduct crosses Grand Union Canal [–with video]

In a juxtaposition of 21st and 18^th century engineering, HS2 has now crossed the Grand Union Canal.

Both pieces of infrastructure run between Digbeth to outer west London, the new railway for 140 miles,  the old canal for 137 miles, and both were the biggest civil engineering projects of their day.

HS2 spans the Grand Union Canal by means of the 3.4km Colne Valley Viaduct in northwest London. The viaduct also crosses the River Colne, local roads and a series of lakes on the outskirts of London between Ruislip and the start of the Chiltern tunnels.

Align, a joint venture  of Bouygues, McAlpine, and VolkerFitzpatrick, is main contractor for this central section of the new London-Birmingham line. The viaduct is mostly being built by a launching gantry that slides along progressively placing precast deck segments in 39 spans. Some 755 of the viaduct's 1,000 deck segments have now been installed, including those across the canal. Each segment weighs up to 140 tonnes.

HS2 Ltd senior project manager Billy Ahluwalia said: “Our work to install the viaduct’s remaining deck segments continues at pace, followed by the installation of the deck edge parapets and noise barriers, before we hand over to Rail Systems for the next major phase of the build programme.”

Align’s surface operations director, Derek Van Rensburg, added: “I would like to highlight the huge contribution made by our subcontractor Kilnbridge that ensured all the piers were constructed safely, to the highest quality and in line with the programme. Working over water with complex structures and temporary works, detailed concrete mix designs and with architectural and design constraints, all led to making these works a major challenge of the viaduct construction. I am pleased to say that the integrated working relationship we established with Kilnbridge made delivering this all part of the day job.”

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