Significant progress has been made on the Northolt tunnel, marking the halfway point in its construction journey.
- Four tunnel boring machines are currently at work to build the longest section of the HS2 railway, making substantial headway.
- The construction involves a twin bore, 8.4 miles each, with remarkable advancements reported by HS2’s contractor SCS JV.
- As the machines reach this crucial milestone, the groundwork is laid for upcoming track and rail system installations.
- Spoil management strategies are in place, repurposing removed earth for ecological and developmental projects across the UK.
The Northolt tunnel project, a significant part of the HS2 railway development, has achieved a crucial milestone with the completion of half of its 8.4-mile twin bored tunnels. This marks a decisive moment in the construction efforts of HS2’s Northolt tunnel underneath London.
Four tunnel boring machines (TBMs) are being utilised to forge the path between HS2’s Old Oak Common station and the outskirts of London at West Ruislip. This project represents the second-longest continuous tunnel on the HS2 railway, following a prominent tunnel through the Chiltern Hills.
The first TBM, named Sushila, commenced its eastward journey from West Ruislip in October 2022, soon accompanied by TBM Caroline. These two machines will each cover five miles, converging at Green Park Way in Greenford, where they will be extracted, symbolising the project’s halfway completion.
In February, TBM Emily initiated her westward path from HS2’s Victoria Road crossover site, subsequently joined by TBM Anne in May. Together, these machines have advanced over 8.4 miles, marking the completed half of the twin-bore tunnel.
The tunnel excavations have meticulously removed nearly two million tonnes of earth. This spoil is pragmatically repurposed: earth from West Ruislip is utilised to reshape a local golf course, while London Clay from Victoria Road is conveyed to the London’s logistics hub, then distributed to Rugby, Kent, and Cambridgeshire for backfilling quarries, supporting housing, and creating wildlife habitats.
The joint venture of Skanska, Costain, and Strabag (SCS JV) leads the tunnel’s construction, also set to undertake the Euston tunnel, contingent upon government approval. James Richardson, the managing director, affirms that reaching the halfway mark reflects substantive progress in this ambitious tunnelling endeavour.
The tunnel fit-out process has commenced, aligning with future track and rail systems installation. Additionally, preparations are underway at Old Oak Common for the assembly and deployment of the final two TBMs, poised to extend the high-speed line into central London.
The Northolt tunnel project continues to progress smoothly, paving the way for future developments in high-speed rail infrastructure.
