The completion of the first major viaduct at HS2’s Delta Junction in North Warwickshire marks a significant milestone as construction accelerates on the high-speed rail line in the region.
A dedicated team of 40 from HS2’s Midlands contractor, Balfour Beatty VINCI, utilized a massive cantilever structure to construct the 472-metre single-track River Tame West Viaduct. This innovative technique, being used for the first time in the UK, involves moving concrete segments into place span-by-span, enhancing efficiency and flexibility in the construction process.
Construction on the viaduct’s piers began in 2023, with the concrete deck construction commencing in early 2024. Since then, 190 pre-cast concrete viaduct segments have been positioned using the specialised cantilever method.
The River Tame West Viaducts will support three rail tracks in total, consisting of one single-track viaduct and one double-track viaduct. Work on the double-track viaduct is currently underway.
These precast segmental viaducts are situated at the northern tip of the Delta Junction – a triangular section of the railway that facilitates train travel between London, Birmingham, and the north. Overall, Delta Junction comprises 13 viaducts and over 10 kilometres of track, enabling HS2 to traverse rivers, existing rail lines, local roads, and motorways.
Sam Hinkley, Lead Senior Project Manager for Delta Junction at HS2 Ltd said:
“The completion of the River Tame West single-track viaduct is a big milestone for the Delta Junction team. In this very complex construction area, we’re building a network of 13 viaducts to carry new high-speed trains over motorways, existing rail lines, rivers and floodplains.
“Nearly 10,000 people in the West Midlands are delivering this world-class engineering, which will lay the foundations for Britain’s future rail network.”
At this location, HS2 is also constructing the single-track River Tame East Viaduct. Additionally, two Water Orton Viaducts are being built on either side of the River Tame West Viaducts, making this one of the most complex sections of the HS2 railway.
For the first time in the UK, the specialist cantilever method is being employed to build nine of the 13 viaducts in Delta Junction, totalling 6,500 meters in length. This process involves installing pre-cast concrete segments produced at HS2’s nearby factory in Lea Marston.
Nicolas Gallone, Pre-cast Segmental Viaducts Project Manager at Balfour Beatty VINCI said:
“This is the first time in the UK we’ve used this innovative technique to build segmental viaducts. It’s an efficient and flexible process using cable stays from the cantilever structure to keep the viaduct in place, while a mast and swivel crane are used to place each segment in place.
“It’s a great achievement for the whole team and work now continues using this technique on the other eight pre-cast segmental viaducts in the Delta Junction.”
The two River Tame West Viaducts span the River Tame near Water Orton, connecting to the Curdworth Box, which will carry high-speed trains over the existing Birmingham to Derby railway.
Construction of the 20 supporting piers for the viaducts began in 2023, with the first spans of the three-track section completed in Spring 2024. This initial phase involved placing segments onto two 42-meter truss beams, moving them into position with a skidding trolley, and securing them using post-tensioning techniques.
Following this, a giant cantilever structure was erected, featuring a 22-meter-high mast, temporary post-tensioning cable stays, and a 14-meter-high swivel crane.
The crane lifts and installs one concrete segment at a time, completing each 45-meter span. The permanent post-tensioning tendons are then stressed to remove the temporary cable stays, leaving the permanent structure securely in place. This process is repeated between each pier until all spans are complete.
Originally developed by Campenon Bernard, now part of VINCI Construction, the mast and swivel crane used on the River Tame West Viaducts are designed and manufactured by BERD.
A team of 40 people is currently involved in the operation, with a total of 2,742 concrete segments to be installed for all nine viaducts using this specialist technique. All deck segments are expected to be in place by late 2026.
Once completed, HS2 will offer more reliable and faster services between London and the West Midlands, with trains continuing to destinations further north via the existing railway. This will alleviate congestion on the southern end of the West Coast Main Line, creating additional capacity for local and freight services.
Image and video credit: HS2
