Work on one of HS2’s most technically demanding sections advanced significantly over the Christmas period, as engineers completed two key viaduct spans over the existing Birmingham to Peterborough railway near Water Orton, Warwickshire.
The newly completed spans form part of the vast Delta Junction – a major triangular interchange taking shape to the east of Birmingham that will enable HS2 services to run to and from the city, while also linking the main high-speed route heading north and south.
Often compared to the nearby Spaghetti Junction for its scale and complexity, Delta Junction comprises an intricate network of viaducts designed to lift high-speed trains over motorways, local roads, operational railways, rivers and floodplains. To support operating speeds of up to 360km/h on the mainline and around 200km/h on the Birmingham approaches, the junction stretches across a much wider footprint than a conventional motorway interchange, with 2.6 miles of track incorporating underpasses, flyovers and five major viaducts.
The Water Orton viaducts lie at the northern end of the junction and will ultimately allow southbound HS2 services to diverge onto the spur serving Birmingham Curzon Street and the rolling stock depot at Washwood Heath.
Engineers working for HS2’s main works contractor in the area, Balfour Beatty VINCI (BBV), made use of a five-day Christmas possession to safely install the two parallel spans across the live railway. During this period, rail services between Birmingham New Street and Coleshill were replaced by buses to allow the works to take place.
With the rail crossing now complete, attention will turn next year to the remaining sections of the structure, including viaduct crossings over the nearby A446 and the M42 motorway.
Sam Hinkley, HS2 Ltd’s Senior Project Manager said:
“It’s great to see the Water Orton viaducts in place across the railway and I’d like to thank everyone who gave up their Christmas to help us reach this important milestone and I’d like to thank passengers for their patience.
“These precast segmental viaducts form a key part of the Delta junction – one of the most complex parts of the HS2 project and I look forward to seeing more progress in the year ahead.”
Once complete, the two single-track Water Orton viaducts will extend for around 1.4km, crossing two separate railways, a river, multiple local roads and the M42. They are being constructed using precast concrete segments assembled through a cantilever process. Following the installation of each span, permanent post-tensioned cables are threaded through the hollow core of the structure, allowing temporary cable stays to be advanced ready for the next stage of construction.
This sequence is repeated between each pier until the full viaduct length is complete. In total, 32 concrete piers – some reaching heights of up to 20 metres – support the Water Orton structures. These piers are cast in situ using bespoke formwork and reinforcement cages produced locally at Coleshill.
The works at Water Orton form part of approximately 3.7 miles of viaduct construction across Delta Junction using the same segmental approach. In total, 2,742 precast concrete segments are required, all of which are being manufactured at a temporary dedicated facility at nearby Lea Marston.
Stephane Ciccolini, Senior Works Manager at Balfour Beatty VINCI, said:
“This complex section of the HS2 route has taken a major step forward, after BBV teams successfully erected two viaducts spans over an existing railway near Water Orton.
“We’ve worked around the clock during the Christmas period to deliver this incredible feat of engineering, using a specialist cantilever technique not seen in the UK before this project. This approach involves using a 22-metre-high mast and a 14-metre-high swivel crane to move each individual segment into place until the span is complete.”
Image and video credits: HS2
