Pioneering HS2: Unveiling the Subterranean Wonder

A specialized team assembles a colossal 1,600-metric-ton machine to excavate Birmingham's Bromford Tunnel for the HS2 project. This giant
HS2Image Source: HS2


A specialized team assembles a colossal 1,600-metric-ton machine to excavate Birmingham's Bromford Tunnel for the HS2 project. This giant tunnel boring machine (TBM), following 'Mary Ann,' embarks on a monumental task, reusing components from the prior TBM, 'Dorothy.' Over 90 engineers meticulously prepare the TBM for its dig, aiming to complete the 3.5-mile tunnel by 2025. The project's sustainability focus involves reusing excavated materials on-site, showcasing technological prowess and local job opportunities.


The construction of the second tunnel boring machine for the HS2's Bromford Tunnel in Birmingham stands as a testament to modern engineering marvels. A 90-member team of specialized engineers from Balfour Beatty VINCI has successfully completed the assembly of this mammoth 1,600-tonne machine. This colossal machinery is all set to commence its mission of excavating the second bore of the Bromford Tunnel next year, marking a significant milestone in the high-speed railway project's progress.

The meticulous assembly operation witnessed the orchestrated movement of various sections of the machine into a 12-meter deep launch pit. Two 600-tonne cranes delicately maneuvered the massive 125-tonne cutterhead into position at the forefront of the 125-meter long TBM within the pit.

The first TBM, named 'Mary Ann,' initiated its excavation from the east portal site near Water Orton earlier this year, already making substantial progress by constructing over 500 tunnel rings, equivalent to 0.6 miles of the 3.5-mile tunnel between North Warwickshire and Washwood Heath in Birmingham.

This second TBM, poised to be launched in the coming spring, remains unnamed for now. 'Mary Ann' is anticipated to break through by the end of 2024, while the second TBM aims to complete its journey by mid-2025. Together, these colossal machines are expected to remove a staggering 1.87 million metric tons of excavated material, which will undergo processing at an on-site slurry treatment plant for reuse across other HS2 sites nearby.

Jules Arlaud, the Tunnelling Director for Balfour Beatty VINCI, expressed, "The completion of the assembly of the second tunnel boring machine marks a monumental achievement for the team involved in the Bromford Tunnel of HS2, representing a complex segment of the new high-speed railway."

As preparations intensify over the next few months, the team will rigorously test and finalize arrangements to ensure the machine's readiness for excavation in the spring of the following year. This massive undertaking demands meticulous planning, including the transportation and reassembly of parts from 'Dorothy,' which forms the core of this second TBM.

HS2's Senior Project Manager, Catherine Loveridge, emphasized the project's peak construction phase, with over 9,750 personnel engaged in the West Midlands, including approximately 450 individuals actively working on-site, many from the local area. The launch of the second TBM promises additional employment opportunities for the community.

The Bromford Tunnel's engineering intricacies involve a concerted effort by around 450 individuals affiliated with HS2's contractor, Balfour Beatty VINCI. A specialized team, including apprentices under BBV's sub-contractor Tunnelcraft, will oversee the TBM's operation 24/7, with each bore expected to take around 16 months to complete.

Rosa Diez, the Tunnels Discipline Lead for Mott MacDonald and SYSTRA's Design Joint Venture, expressed pride in witnessing the second TBM's positioning, signifying a collective learning journey from past excavations. This colossal effort involving 41,594 concrete segments will contribute to the creation of 5,942 rings for the twin bore tunnel, each weighing 49 tonnes.

The production of these segments, occurring at Balfour Beatty VINCI's pre-cast factory near Bristol, incorporates sustainable practices, utilizing Ground Granulated Blast-furnace Slag to reduce the cement content's carbon footprint by 40%. Advanced 3D scanning techniques ensure precision during the segment production process.


The deployment of the second giant tunnel boring machine underlines a pivotal chapter in HS2's Bromford Tunnel project, showcasing remarkable engineering feats and sustainable construction practices. This endeavor not only embodies technological innovation but also promises employment opportunities for the local community, setting a precedent for future infrastructure initiatives.

Related Stories

No stories found.
SteelGuru Business News