Engineering landmarks meet as HS2 crosses Grand Union Canal

The 21st and 18th centuries have come together as the UK’s longest railway bridge has crossed the country’s longest canal.

New images show the most recently completed section of HS2’s Colne Valley Viaduct after deck segments were laid to span the Grand Union Canal near Denham.

They juxtapose the new 140-mile high speed London-Birmingham railway against the 18th century’s solution to connecting Britain’s two largest cities.

Both pieces of infrastructure were built under powers granted by Act of Parliament, arrive in the Birmingham district of Digbeth, are similar lengths – HS2 is 140miles and the canal is 137 miles – and both were the largest civil engineering endeavours of their time.

The two differ dramatically in other respects. Compared to the sedate progress of canal boats high speed trains will travel across the 2.1mile viaduct at speeds of up to 200mph, completing the journey between the capital and Britain's second city in just 49mins. 

Uniquely shaped and weighing as much as 140 tonnes , 755 of the viaduct's 1,000 deck segments have been installed creating 39 spans over land and water for 1.5 miles.

News comes after construction of all the viaduct's 56 supporting piers was completed in advance of the deck being installed above. 

HS2 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.”

Viaduct construction is led by HS2’s main works contractor Align JV – that includes Bouygues Travaux Publics, Sir Robert McAlpine and Volker Fitzpatrick.

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.”