Balfour Beatty Vinci completes final HS2 Birmingham tunnel

Photo: Balfour Beatty

The TBM, launched near Water Orton in March 2024, is one of two identical machines used to dig the 3.5 mile (5.6 km) Bromford tunnels that will carry high-speed trains beneath the M6 and the eastern outskirts of the city.

The first TBM completed its drive earlier this year.

Together, the two machines excavated more than 1.8 million tonnes of material and installed 5 804 concrete ring segments to form the twin eastbound and westbound tunnels.

The excavated Mercia Mudstone is being reused to landscape the railway approaches into Birmingham.

The breakthrough marks the completion of all 28 miles (45 km) of deep-bore tunnelling between Old Oak Common in west London and Birmingham Curzon Street.

Balfour Beatty said work will now focus on internal structures, including concrete base slabs, ventilation shafts, walkways and cross passages.

Jules Arlaud, tunnelling director, Balfour Beatty Vinci, said, “Today is a historic moment for Balfour Beatty Vinci, as TBM Elizabeth completes her three-and-a-half-mile journey in Washwood Heath. This is Balfour Beatty Vinci’s fourth and final TBM breakthrough, delivered by our expert tunnelling team who’ve worked around the clock over 19 months to arrive at this point.

“A sense of achievement and pride is felt by everyone connected with the project and follows years of planning and preparation. This has allowed us to guide Elizabeth safely and successfully underneath complex ground conditions and critical live infrastructure, including energy networks, the M6 and the River Tame. A breakthrough is always a unique moment, and it marks the culmination of exceptional engineering, dedication, and collaboration.”

Alan Morris, HS2 Ltd’s construction delivery director added that it marks a major milestone for the for the HS2 project.

He said, “All eight of the TBMs digging our tunnels between Old Oak Common and Curzon Street have now broken through, which means that the focus is now on the internal concrete work, ventilation shafts and cross passages.

“I’m immensely proud of the men and women who have worked round the clock to bring our TBMs and their crews home safely, and I look forward to seeing more progress inside the tunnels in the years ahead.”

The Washwood Heath site will later become HS2’s depot and Network Integrated Control Centre, managing the servicing, storage and real-time operation of the railway once it opens.