The first two tunnel boring machines (TBM) for the HS2 tunnel project in London will be delivered by the end of 2021. The contract for the two 9.84 m diameter machines is a significant milestone for the southern stretch of the massive 51.5-km (32-mile) HS2 project.

HS2’s Main Works Civils Contractor, Skanska Costain STRABAG JV (SCS JV), signed the contract for the TBMs that are designed and manufactured specifically for the London clay and chalk ground conditions they will bore through.

The London tunnels for HS2 are twin bored, and will be just under 21 km (13 miles) each way, and with a combined total of 41.6 km (25.8 miles), the HS2 London tunnel’s will be the same length as Crossrail. This program of tunneling between central London and the M25 will be undertaken by SCS JV. Overall there will be 10 TBMs purchased to construct the 102.4 km (63.6 miles) of tunneling along the HS2 route between the West Midlands and London.

These first two London TBMs will be launched from a portal at West Ruislip and will travel 8 km (5 miles) east, creating the western section of the Northolt Tunnel. Once they arrive at Green Park Way in Greenford the machines will be extracted from the ground and the site will then be used as a vent shaft. The 13.4 km (8.3 miles) tunnel will be completed with a 5.4 km (3.3 miles) tunnel drive from Old Oak Common using two further TBMs which are yet to be procured. A second tunnel between Euston and Old Oak Common will complete the remaining 7.2 km (4.5 miles) of London tunnel between the two HS2 stations.

Once the first new TBMs have been built, they will be transported by sea before being delivered to site at the end of 2021. Once assembled, they will begin the tunnel drive from mid 2022, until completion at the beginning of 2024.

James Richardson, Managing Director of Skanska Costain STRABAG joint venture (SCS JV) said: “As the construction partner responsible for the majority of tunnels on the HS2 project, our contract for the first two TBMs is a major milestone for us. This partnership with Herrenknecht has brought together leading expertise in both our organisations and together we are constructing some of the most advanced TBMs in the world to efficiently drive the tunnels under London.

Work is already well underway to prepare for the first tunnel launch in 2022. Throughout these and all our activities we are committed to involving local communities and stakeholders and supporting social development and employment through the 4,500 jobs that will be created.”

David Salameh, Head of Project Management Traffic Tunneling at Herrenknecht said: “We feel honored to be part of the epoch-making HS2 project and especially to work with the SCS Joint Venture. Our two Herrenknecht machines will be specially and innovatively designed for this project, excavating the Northolt Tunnels West.”