How HS2 built the ‘UK’s longest railway bridge’


HS2 has completed foundation works for the “UK’s longest railway bridge”marking the end of almost two years of work. 

Colne Valley Viaduct
Credit: HS2
by Rory ButlerJanuary 31, 2023

The 3.4 km Colne Valley Viaduct will be 100 m longer than Dundee’s Tay Bridge, which currently holds the title. 

The project involved the installation of 292 concrete piles – some to a depth of 60 m – that will bear the new high-speed rail line across a series of lakes and waterways near Hillingdon. 

Separate teams constructed 56 huge piers and the deck on top in parallel.  

The deck is being built in 1,000 separate parts at a temporary factory nearby and then assembled and lifted into position. 

Colne Valley Viaduct
Credit: HS2

More than 500 m of the viaduct is now standing, roughly 10 m above the water. 

To install the 66 piles in the lakebed, teams built more than 1 km of temporary jetties to transport materials and equipment, with cofferdams (an enclosure built within a body of water) to hold back the water around each foundation.  

The team 

Align JV: Bouygues Travaux Publics, Sir Robert McAlpine, VolkerFitzpatrick 

KVJV: Keller Group, VSL International 

HS2 cost and delivery 

HS2 was in the news last week after concerns over delays and the completion of the new railway line were raised. 

Inflation rates and rising costs brought HS2 under more scrutiny, with fears the line might not reach Euston in central London, as well as delays setting its completion in 2038. 

However, Chancellor Jeremy Hunt quashed reports, assuring it would be completed into London. 

HS2 runs from London to Manchester through Birmingham. 

Its initial budget in 2015 was £55.7 billion. Recent estimates however put the total closer to £100 billion. 

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