A magnificent project

SCS JV is part of an incredible journey, creating the London tunnels section of a new high-speed railway.

HS2 takes fast trains off the existing railway and on to their own dedicated tracks, better connecting our major towns and cities. This extraordinary project involves:

  • 30,000 workers
  • 343 miles of railway track
  • 37 miles of viaducts
  • 45 miles of tunnels

SCS JV is constructing 13 miles of twin-bore tunnels on the HS2 route to its southern terminus at Euston. As 95% of this journey will be in tunnel, we will run six TBMs, of which five will operate simultaneously.

HS2’s tunnels are built using different construction techniques to suit their purpose and local conditions. A green tunnel is where a trench is excavated and roofed over, and the land on top is blended into the landscape. A twin-bore tunnel is where two parallel tunnels, each containing a single rail track, are constructed using tunnel boring machines (TBMs). A rotating cutter-head at the front of the TBM bores the tunnel and the TBM installs the round concrete segments that form the tunnel walls.

Pioneering project under way

Project map

How we are building HS2 London tunnels

The project has been divided into three areas – west, central and east – each with its own dedicated team. A fourth team takes care of logistics across all the areas. Here’s an overview of what each team is doing.

West area

The West team covers multiple sites in and around the area between Greenpark Way and West Ruislip. As well as building two ventilation shafts at Mandeville Road and South Ruislip, we’ve also constructed a huge tunnel portal at West Ruislip. Trains enter and exit the tunnels to travel 13 miles underground to and from Euston.

The first two of six tunnel boring machines (TBMs) are launched from West Ruislip, travelling five miles to Greenpark Way. We’ll use all material excavated by these first two TBMs within the site to create embankments adjacent to the train line. These will run outside the tunnels between West Ruislip and the Europe’s longest rail bridge, the Colne Valley viaduct. This is being constructed by HS2’s principal partner Align Joint Venture.

Each vent has two shafts to minimise earth movements22m + 13m

Landscape feature created from excavated clay18m high

West Team Photo

Central area

Our Central team covers a large area between Adelaide Road in Camden and Greenpark Way in Ealing. The section includes five ventilation shafts that support the tunnels running up to 50 metres below London. It also includes the Victoria Road Crossover Box, a large structure that will allow trains to cross tracks just outside the platforms to the new Old Oak Common station.

A huge logistics hub manages all our security and vehicle movements across London. These include the removal of spoil material by rail and delivery of segment rings for the majority of our tunnelling programme. We’re also contracting a tunnel between the logistics hub and Old Oak Common station, as well as a large conveyor system covering sites in the Park Royal area, so material can be transported without the need to use local roads. These initiatives are helping us take up to one million lorry movements off London’s roads.

We are building a 140m long, 25m deep crossover box140m

A 800m long dedicated logistics tunnel will remove lorries from Londons roads800m

Central Team

East area

The most compact of our work sites, this is where HS2 emerges from the tunnels on its final 0.6-mile route to Euston station. We are creating a crossover cavern, where trains can switch tracks underground before rising to the surface via a ramp of reinforced concrete troughs. Bridges at Granby Terrace and Hampstead Road are being extended for tracks to pass under. All these structures require piling, or deep foundations, to support them. We have pioneered a method of removing waste concrete from piles that massively reduces noise and dust affecting neighbouring homes, and minimises the use of pneumatic tools.


cranes along narrow site5

East team - Euston Station


Based at Willesden terminal, we look after logistics for all 22 work sites. Our biggest challenge is disposing of excavated earth. As TBMs move their way through the ground they throw waste out the back. This earth is carried on nine miles of conveyors through dedicated tunnels to Willesden, where it is loaded on to trains and taken to landfill. Using eight trains a day removes 20 lorries from the road, saving 40% in CO2 emissions. We also manage logistics for 400 to 500 HGVs entering the site daily, and incident control and security. We work with stakeholders and communities to minimise the impact on them.

Tonnes of material moved through Willesden site5.6 million

Interventions remove need for1 million lorries


Be part of something amazing

We are searching for talent in the local community to help us build HS2 London tunnels. This includes providing the most vulnerable in society with the skills and confidence to enter the workforce, and striving to upskill and retain talent in the industry. Here’s how we’re pushing boundaries.

Our return-to-work programme supports professional men and women who have taken a career break, by placing them in a team where their skills and experience are valued. We also work with local charities and partners to offer placements and employment for those most in need.

Hundreds of apprentices will be taken on in roles from site operatives to commercial and civil engineering positions.

Our values

Our values support us to deliver on our purpose. They ensure we leave a positive legacy for our communities and our industry long after the project is completed

We take care and responsibility for the wellbeing of the HS2 family, our people, our families, and the communities and environment in which we work – now and in the future. We work safely or not at all.

We work collaboratively as one team towards a common goal. We build trusting relationships by communicating clearly and honestly. We celebrate diversity in our team, recognising and rewarding our people for effort and achievement.

We support each other to do things right first time. We strive to continuously improve and learn lessons. We are open to new ideas. We work with our people and our supply chain to innovate and embrace new technology.

We empower all our staff to lead by example. We are what we do, not just what we say. We will create a high-performing environment where our people feel engaged and motivated to do their best work.

We hold ourselves to account and always do the right thing. We create an ethical and open culture. We are mindful of our actions and consider their impact on others. We resolve conflict by acting flexibly, listening and being open-minded.


About the joint venture

The HS2 London tunnels team is a joint venture of Skanska, Costain and STRABAG. The individual companies have delivered high-speed rail and major infrastructure internationally and we have a proven record of working together. We bring together an industry-leading combination of tried, tested and successful partnerships, world-wide high-speed rail experience and extensive national and regional knowledge.

The joint venture is delivering the High Speed Two (HS2) Main Works Civil Contract for Phase 1 of the route, the HS2 London tunnels. Find out more about the joint venture partners and the project by clicking the links below.