Engineers have begun assembling two giant tunnelling machines that will dig
the final 4.5 miles of underground high-speed railway – carrying HS2 trains
into the heart of London.
Weighing an incredible 1,250 tonnes, each of the tunnel boring machines
(TBMs) will launch from an underground box at one end of the project’s Old Oak
Common station. They are expected to take around one and a half years to reach
the railway’s final southern terminus at London Euston.
As well as taking passengers closer to central London, the extension to
Euston will create additional capacity on the new high-speed line, allowing
more services to run to more destinations across the Midlands and the North.
Arrival of the line into Euston is also expected to trigger a transport-led
regeneration of the area – unlocking opportunities for thousands of new homes
and jobs.
In keeping with tradition, the TBMs have been given female names after
prominent women in history. One machine is called Karen after Karen Harrison,
the first female train driver in the UK who was based out of Old Oak Common
depot. The second is named Madeleine, after Madeleine Nobbs, the former
president of the Women’s Engineering Society.
The unveiling of the TBMs – the final set to be launched for the railway
between London and the West Midlands – marks another significant milestone for
HS2.
It comes on the day that Mark Wild joins HS2 Ltd as the company’s new chief
executive. Mr Wild, former CEO of Crossrail, will help oversee the project’s
transition from a major construction programme to a working railway, with a
renewed focus on controlling costs.
Rail Minister Lord Hendy said:
“I’m delighted to welcome Mark Wild to HS2 and look forward to working with
him to successfully deliver Britain’s largest rail project sensibly and
efficiently for the benefit of passengers and taxpayers.
“The sheer scale of the progress at Old Oak Common – and the benefits we
will realise from taking HS2 to Euston, as confirmed in the Budget - reminds us
that this is a once-in-a-generation project. HS2 will not only improve
transport links for millions but unlock huge potential for growth, jobs and
regeneration right across the country.”
The Mayor of London, Sadiq Khan,
said: “After so much uncertainty, it’s great to
finally be working with a Government that recognises the huge importance of
this scheme to London and the UK, and understands why terminating HS2 at Euston
is so important. It’s exciting that these tunnel boring machines will soon be
getting work underway.
“This is another example of the difference that the new Government’s
approach is making in London, delivering real benefits that will help to
build a fairer and greener London for everyone and deliver the change Britain
needs.”
Huw Edwards, Stations Delivery
Director, HS2 Ltd, said: “We welcome the commitment from
the government to build HS2 all the way to Euston and preparations to tunnel
from Old Oak Common are now well underway.
“A terminus station for HS2 in the heart of the capital will provide a vital
gateway for passengers travelling to and from the Midlands and North, and will
undoubtedly lead to the transport-led regeneration of Euston – supporting
growth in the local economy and creating thousands of new homes and jobs.”
The two 190m-long TBMs were manufactured by world-leading tunnelling experts
Herrenknecht AG in Germany and were transported to Old Oak Common in pieces
before being reassembled on site. This summer, the HS2 team lifted the machines
into the underground station box using a 750-tonne crane. They are now being
reassembled at the eastern end of the station, ready to bore to Euston.
The cutterhead of the machine, which has been optimised to cut through
London clay, is 8.53m across with the inner diameter of the tunnel set to be
7.55m.
The TBMs are like underground factories, excavating the tunnels using a
turning cutterhead, lining them with pre-cast concrete tunnel segments,
grouting them into place before moving forward at an average speed of 16 metres
per day. Teams work around the clock below ground on the along with teams on
the surface supporting them.
HS2’s London tunnels contractor, Skanksa Costain STRABAG (SCS) joint
venture, is leading construction of the twin-bored tunnel. In January 2024 the
team completed a logistics tunnel from a nearby site at Atlas Road which will
provide access for materials, and a route to remove the London Clay being
excavated by the machine. It has also built two spray concrete-lined tunnels
from which the TBMs will be launched eastwards towards Euston. Boring is
expected to begin in 2025.
SCS is already well advanced with construction the Northolt tunnel – a
separate structure running west out of Old Oak Common towards West Ruislip,
outer London.
James Richardson, Managing
Director, SCS JV, said: “We are delighted that the
Government has given the green light to delivering HS2 through to Euston,
ensuring the full benefits of the new railway are realised. Over the past two
years, we have continued with critical activities to ensure that we can deliver
the Euston Tunnel and approaches quickly, and at the lowest possible cost.
“We are also making excellent progress on the tunnelling between West Ruislip
and Old Oak Common, with four TBMs in operation, and the works well over 50%
complete.”
The machines will complete their journeys underground and the outer can of
the machine will be left to form part of the tunnel. The mechanical components
of the TBMs will be pulled back through the 4.5 mile tunnel and disassembled.
The approach to Euston will be completed by spray concrete lined tunnels
which will then transition into three tunnels, which will enable trains to be
fed into and from platforms at Euston station.
Final plans for the future HS2 terminus station at Euston are still under
review and HS2 Ltd is continuing to work with the Government and other
stakeholders to design an affordable station design that can run HS2 services
from London to the Midlands. Further details will be announced by the
Government in due course.
