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Final HS2 TBM begins boring in the West Midlands

HS2 launched the last tunnel boring machine (TBM) on March 5 to dig tunnels for the new high speed railway in the West Midlands.

The 125 m (410 ft) long TBM has started on its journey to dig the second bore of HS2’s Bromford Tunnel, between the east portal at Water Orton in North Warwickshire and the west portal at Washwood Heath in Birmingham.

The 5.6 km (3.5 mile) twin bore tunnel will take high speed trains in and out of Birmingham, with a series of viaducts between Washwood Heath and Curzon Street Station taking trains to the city center.

The first TBM, which launched in June 2023 and was named ‘Mary Ann’ – the real name of Warwickshire-born author George Eliot, has completed around one third of her journey digging toward Birmingham. So far, the machine has tunneled under the Park Hall Nature Reserve, is currently near the River Tame, and will continue adjacent to the M6 at a depth of 27 m (89 ft) before breaking through at Washwood Heath later this year. The second TBM is due to finish its journey in Autumn 2025.

The full Bromford Tunnel program is being delivered by around 450 people working for HS2’s contractor Balfour Beatty VINCI (BBV). A specialist tunneling team working for BBV’s sub-contractors Tunnelcraft and Solihull-based Rorcon, are operating both TBMs 24/7, with each bore taking around 16 months.

Following the tradition of naming HS2 TBMs after famous women from the local area, pupils from Paget Primary School in Birmingham chose to call the machine ‘Elizabeth’ after Dame Elizabeth Cadbury, who spent her life campaigning for the education and welfare of women in Birmingham.

“It’s fantastic to see this last West Midlands TBM get underway, marking another key moment for HS2 in the region,” Catherine Loveridge, HS2’s Senior Project Manager said. “We’re now at peak construction on the project, delivering these massive feats of engineering using many local companies and local skills.

“Over a third of our total HS2 workforce are based at worksites across the West Midlands, and thousands more jobs are still to be created locally as work to build Curzon Street Station, Interchange Station and the Washwood Heath Depot gathers momentum.”

“Today marks Balfour Beatty VINCI’s fourth and final TBM launch – an incredible moment for our tunneling team who have worked tirelessly to achieve this milestone,” said Jules Arlaud, Tunnelling Director for Balfour Beatty VINCI. “As ‘Mary Ann’ continues her journey towards Washwood Heath in Birmingham, we’re now looking forward to having two machines underground, as this fascinating and complex stretch of the HS2 route inches another step closer to completion.”

Tunnelcraft have recruited nine tunneling apprentices, including formerly unemployed people from the local area, providing a unique opportunity to learn new skills and start a new career.

Both TBMs will remove a total of 1.87 Mt (2 million st) of excavated material, which is sifted at the on-site slurry treatment plant and reused on HS2’s nearby sites at Delta Junction, where a complex network of 13 viaducts is being built. HS2 has built dedicated roads between these construction sites, including an access off the M6/M42 link roads, in order to take lorries off public roads.

Working as an ‘underground factory’, both TBMs will put a total of 41,594 concrete segments in place, creating 5,942 rings to make the twin bore tunnel, with each ring weighing 49 t (54 st). The segments are being produced at Balfour Beatty VINCI’s pre-cast factory at Avonmouth near Bristol.

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