The High Speed 2 project has achieved a major milestone with the completion of excavation works for the Northolt Tunnel in London. This 13.4 km tunnel forms one of the longest underground sections of HS2 and represents a critical link on the route into central London.
The Northolt Tunnel passes beneath densely built areas of the capital, requiring advanced engineering to manage geotechnical risks while protecting surface infrastructure and communities. Successfully completing the excavation has demonstrated the project’s ability to deliver under highly complex conditions.
The drive was completed using specialised tunnel boring machines designed for extended continuous excavation, ensuring efficiency and precision throughout the process.
This milestone brings HS2 closer to realising its ambition of delivering faster, greener rail connections between London, the Midlands and the North of England.
Completing the tunnelling ahead of schedule has allowed work to transition quickly into the next stages, including tunnel lining, track installation and fitting out with ventilation, power and safety systems.
The project has been delivered with strict adherence to environmental monitoring and safety standards. These included continuous checks for ground settlement, water ingress and vibration control.
The tunnel drive has also contributed to workforce development, providing valuable skills and training opportunities for young engineers and apprentices.
By finalising excavation, HS2 continues to reinforce its position as a transformative transport project that will reshape connectivity, regional growth, and sustainable travel across the UK.