Construction of one of the most complex elements of HS2 moved forward over the Christmas period, with engineers completing two critical viaduct spans over the existing Birmingham to Peterborough railway near Water Orton in Warwickshire.
The works form part of the Delta junction, a vast triangular interchange east of Birmingham that will connect HS2 services running to and from Birmingham with the main high-speed line heading north and south. Comparable in complexity to the nearby Spaghetti Junction, the Delta junction is made up of a series of interlinked viaducts carrying the new railway over motorways, roads, rivers, floodplains and existing rail infrastructure.
To achieve the high operating speeds required on HS2 – up to 360km/h on the mainline and around 200km/h on approaches to Birmingham – the junction extends across a wide area. In total, it will include 2.6 miles of track, incorporating underpasses, flyovers and five major viaduct structures.
At the northern end of the junction, the Water Orton viaducts will allow southbound trains to join the spur into Birmingham Curzon Street, as well as providing access to the rolling stock depot at Washwood Heath. Using a five-day railway closure over the quieter Christmas period, engineers from HS2’s main works contractor, Balfour Beatty VINCI, safely installed two parallel spans over the live Birmingham to Peterborough line. During the closure, buses replaced trains between Birmingham New Street and Coleshill.
With the railway crossing now complete, attention will turn next year to extending the viaducts over the nearby A446 and the M42 motorway.
Sam Hinkley, senior project manager at HS2 Ltd, said the milestone marked important progress on a challenging section of the route.
“It’s great to see the Water Orton viaducts in place across the railway,” he said. “I’d like to thank everyone who worked through the Christmas period to reach this point, as well as passengers for their patience while the line was closed.”
When finished, the two single-track Water Orton viaducts will stretch for around 1.4km, crossing two railways, a river, local roads and the M42. They are being built using a precast segmental construction method, with concrete segments lifted into position using a cantilever technique. Once a span is assembled, permanent post-tensioning cables are installed through the hollow structure, allowing temporary support cables to be moved forward ready for the next section.
The Water Orton structures form part of 3.7 miles of viaducts across the Delta junction being delivered using this approach. In total, 2,742 precast concrete segments are being manufactured at a temporary facility at nearby Lea Marston, while the 32 supporting piers – some reaching 20 metres in height – are cast in situ using bespoke formwork produced at Coleshill.
Stephane Ciccolini, senior works manager at Balfour Beatty VINCI, said the Christmas works represented a significant engineering achievement.
“Our teams worked around the clock to safely erect two viaduct spans over an operational railway,” he said. “The specialist cantilever technique we’re using, which involves a 22-metre mast and a swivel crane to position each segment, has not been used in the UK before HS2 and allows us to deliver these structures with precision while keeping disruption to a minimum.”
With further phases planned in 2026, the Delta junction remains one of the most technically demanding parts of the HS2 programme, and a critical component in delivering high-speed services into Birmingham.
