HS2 Completes Major Viaduct Deck Construction at Delta Junction Near Birmingham

HS2 has reached a significant construction milestone after completing four parallel viaduct decks at the complex Delta Junction to the east of Birmingham.

The structures, each stretching more than 600 metres, sit near Coleshill in Warwickshire and form part of the vast Delta Junction network. This intricate arrangement of flyovers, bridges and underpasses will carry high-speed trains over existing motorways, local roads, railway lines, rivers and floodplains.

The newly completed Coleshill East and West viaducts make up the southern section of the junction, where the railway divides before crossing a local road and the River Cole floodplain between the M6 and M42 motorways.

Two of the viaducts will carry the four-track HS2 mainline running north to south. Flanking these are two narrower structures designed to take services in and out of the new Birmingham Curzon Street station. Altogether, the viaduct structures at this location extend for around 2.4 kilometres.

The decks have been assembled from 1,024 precast concrete segments manufactured off-site in Kingsbury before being transported to Coleshill. Each segment was lifted into position and secured using a cantilever construction method.

The central deck measures 22 metres in width and consists of twin rows of 11-metre-wide sections, each weighing approximately 60 tonnes. The two single-track viaducts were formed using individual rows of segments weighing around 44 tonnes apiece. The entire structure is supported by 54 reinforced concrete piers, some rising up to 12 metres high.

Balfour Beatty VINCI is delivering the viaducts on behalf of HS2. During construction, steel cables temporarily held the segments in place until each span was completed. Permanent post-tensioning cables were then installed through the centre of the deck to strengthen the finished structure.

With the main deck installation now complete, work will shift to final elements including kerbs and parapets.

Caroline Warrington, Head of Delivery at HS2 Ltd, said the Delta Junction is a vital component of the wider project.

“HS2 will transform journeys between our two largest cities, while freeing up space on the existing West Coast Main Line for more freight and local services,” she said.

“The Delta forms a key part of the project and it’s great to see it starting to come together. I’d like to thank everyone involved in the Coleshill viaducts and look forward to seeing more progress in the year ahead, as the focus turns to completing the robust kerbs and parapets.”