Europe’s largest vertical shaft sinking machine (VSM) has got to work as part of National Grid’s Grain to Tilbury project.

The VSM has the largest diameter ever of any VSM in Europe and is the largest supplied by Herrenknecht, with works being delivered by Ferrovial BEMO JV.

Launched at Tilbury in Essex, the Grain to Tilbury scheme is a critical part of National Grid’s Great Grid Upgrade, designed to future-proof the UK’s electricity transmission network. The project will replace the existing 1960s Thames Cable Tunnel between Tilbury and Gravesend, which has reached the end of its useful life.

The machine has been named Verena after Verena Holmes, a pioneering British mechanical engineer and the first female member of the Institution of Mechanical Engineers.

Ferrovial BEMO JV has been awarded the contract to build a 2.2km-long high-voltage (400kV) cable tunnel, with the VSM designed and built by Herrenknecht AG. This purpose-built approach represents a significant innovation for UK shaft construction, offering improved safety, speed and environmental performance.

The VSM has now been deployed to construct the 15m internal diameter shaft at Tilbury, reaching a depth of just over 48 metres. Once complete, a second shaft will be constructed at the project’s Gravesend site.

The VSM is remotely operated from the surface and removes the need for operatives to enter the shaft during construction.  The VSM cutting drum operates within a water-filled shaft, eliminating the need for groundwater lowering or treatment.  The shaft is carefully lowered from the surface as the excavation progresses.  This all helps to ensure safe, efficient progress through challenging geology.

Mark Farmer, project director for National Grid, said: The” Grain to Tilbury project is helping to future-proof the UK's electricity network. The launch of the Vertical Shaft Sinking Machine marks a major milestone for the project. Through collaboration and innovation, this technology is helping to deliver resilient infrastructure under the Thames, securing reliable electricity for the decades ahead.”