The High Speed 2 (HS2) project marks a significant milestone as the tunnel boring machine (TBM) Mary Ann reaches halfway through the Bromford Tunnel.
- Mary Ann, a 125m long TBM, has bored 2.8km of the twin-bore tunnel since its launch from Water Orton last year.
- The TBM operates 40m underground, moving towards Washwood Heath, passing under notable landmarks such as the Park Hall Nature Reserve.
- A second TBM, Elizabeth, began its journey in March, with its own anticipated milestone by the end of 2025.
- This engineering endeavour has engaged over 180 specialists, including local apprentices, contributing significantly to the HS2 infrastructure.
The ambitious High Speed 2 (HS2) project continues to make headway with a notable achievement on the Bromford Tunnel. The first of two 5.6km tunnels to Birmingham is halfway completed by the tunnel boring machine (TBM) named Mary Ann. Since its deployment from a substantial underground box at Water Orton last year, Mary Ann has successfully advanced 2.8km through the challenging subterranean terrain, demonstrating engineering precision and efficiency.
Placing pre-cast concrete segments as it progresses, Mary Ann constructs sturdy tunnel linings. In total, this process will require the installation of 20,797 segments to form 2,971 rings. This achievement was marked by the TBM passing the 47m deep and 18.6m diameter ventilation shaft at Castle Vale, a key feature that will ensure adequate ventilation and emergency access between the tunnels. The completion of the headhouse topping this structure is anticipated to occur by 2027.
Simultaneously, a second TBM, Elizabeth, embarked on its journey through the parallel tunnel in March, aiming to complete its excavation by late 2025. These twin undertakings collectively involve the removal of approximately 1.87 million tonnes of excavated material, expertly processed at the on-site slurry treatment facility. This material is then repurposed at the nearby Delta Junction, where an intricate network of 13 viaducts is under construction.
This project not only highlights the technical prowess of the involved organisations such as Tunnelcraft and Rorcon, but it also underscores a commitment to community engagement through the employment of 10 apprentices from the local area, including previously unemployed individuals. Such efforts illustrate the project’s broader socio-economic impact, as noted by Labour MP Liam Byrne, who praised the initiative’s contribution to local employment and its status as an exemplar of world-class engineering.
Progress continues at the Washwood Heath site, where a sizable earthworks operation has produced the deepest tunnel portal on the route at 22 metres below ground level. As trains exit the Bromford Tunnel, they will pass through a 750m cut-and-cover section before ascending onto viaducts leading into Birmingham’s Curzon Street station. As this phase advances, anticipation builds towards the eventual completion of both tunnels and their integration into the broader rail network.
Reaching this milestone is a testament to the engineering skill and collaborative effort driving the HS2 project forward.
