Bromford Tunnel

The Bromford Tunnel is a 3.5-mile (5.8km) twin-bore tunnel connecting Water Orton in North Warwickshire to Washwood Heath in Birmingham. Two giant tunnel boring machines (TBMs), TBM Mary Ann and Elizabeth, are being used to excavate the tunnel. TBM Mary Ann completed her journey in May 2025, with TBM Elizabeth still advancing through the second bore.

Tunnel construction

The construction of HS2’s gateway to Birmingham is being created by two huge 125-metre-long tunnel boring machines. The first machine, named TBM Mary Ann, was launched in August 2023 while the machine digging the second bore, named TBM Elizabeth, was launched in March 2024.

Driving around 40 metres underground from Water Orton towards Birmingham, the TBMs were tasked with excavating under the Park Hall Nature Reserve, the M6 motorway, and the meandering River Tame, which will be crossed four times, before breaking through at Washwood Heath.

The 1,600-tonne TBM Mary Ann broke through in May 2025, after a 22-month-long mission. The second bore is expected to be completed later in 2025.

The tunnel breakthrough site in Washwood Heath, will soon become the nerve centre for HS2’s operations. Next to the tunnel portal, HS2’s Depot and Network Intergrated Control Centre will be built. From this site, trains will be serviced and stored, and the real time operation of the railway will be controlled.

Washwood Heath Depot

Tunnelling excavation

An expert tunnelling team have been working around the clock on shifts to operate the machines, which build the tunnel as they excavate. In fact, 1.87 million tonnes of material will be excavated and sifted at the on-site slurry treatment plant to be reused on nearby sites at the Delta Junction.

Following the excavation, teams will begin fitting out the tunnel with cross passages, concrete finishing works and base slabs, and emergency and maintenance walkways.