Sushila's Triumph: Five Miles of Tunneling Success for HS2 in London

The HS2 project celebrates a significant engineering achievement as Tunnel Boring Machine (TBM) Sushila successfully completed a five-mile journey, breaking through into the Green Park Way vent shaft in Ealing. This breakthrough marks a crucial step in constructing the Northolt Tunnel, which will connect West Ruislip to Old Oak Common, bringing HS2 closer to its vision of high-speed connectivity between London and Birmingham.

The Northolt Tunnel features twin-bored tunnels stretching 8.4 miles, constructed by four TBMs: Sushila, Caroline, Emily, and Anne. Sushila, the first to launch in October 2022, has now paved the way by installing 4,217 tunnel rings and excavating over 1.2 million tonnes of earth. The operation utilized innovative engineering, including a reception can filled with foam concrete, to manage high water pressure and ensure precise alignment and safety.

Each TBM operates as an underground factory, excavating soil, placing pre-cast concrete segments, and grouting them into place. The excavated material has been repurposed to create wildlife meadows and wooded areas, aligning with HS2’s Green Corridor initiative.

The breakthrough is the first for the Northolt Tunnel, with three additional TBMs continuing their progress. Sushila’s successful journey is a testament to the teamwork and expertise of global engineering efforts. The 160-meter-long TBM, weighing 2,050 tonnes, worked tirelessly at an average speed of 16 meters per day.

This milestone is part of a broader sustainability effort, with HS2 minimizing environmental impacts through innovative construction methods and reusing excavated materials for ecological restoration. The project exemplifies how cutting-edge engineering can merge infrastructure development with environmental stewardship.

The completion of Sushila’s five-mile tunneling journey showcases HS2’s engineering innovation and commitment to sustainability. As work progresses on the remaining sections, the Northolt Tunnel takes HS2 one step closer to revolutionizing high-speed rail travel in the UK.