High Speed 2 (HS2) Tunnelling

“Celia” the second giant tunnel boring machine in the Chilterns

The new machine is named after Cecilia Payne-Gaposchkin, a Wendover astronomer. The name was chosen by a public vote after being nominated by students at neighbouring Chalfont Community College.The first machine, dubbed “Florence,” so named after Florence Nightingale was deployed in May 2021.

The construction of the new railway is split into three phases:Phase One linking London and the West Midlands;Phase 2a linking the West Midlands and the North via Crewe; andPhase 2b completing the railway to Manchester, the East Midlands and the North.

The route segments between London and West Midlands will include tunnels at Ruislip and the Chilterns Area of Outstanding Natural Beauty (AONB). Sections near Turweston, Chipping Warden, Southam and Burton Green will consist of cutting and tunnel segments.

HS2 Tunnel Boring Machines (TBMs)

The machines are operated by HS2’s main works contractor, Align JV and launched from a site by the M25 to the northwest of London.HS2 will utilise 10 machines in total throughout construction, and 64 miles of tunnels between London and the West Midlands.The two machines will excavate separate northern and southbound tunnels while working side by side.

These huge machines, according to HS2, were developed particularly for the combination of chalk and flints beneath the Chilterns, and are driven by zero-carbon energy, and can move up to 20 metres per day.

Six gantries mounted on enormous rollers are located behind the cutterhead, providing everything from a system that mechanically erects tunnel lining pieces to a canteen and restroom facilities for the tunnellers on board.

Each machine works independently,akin to asubterranean factory, excavating the tunnel, lining it with concrete wall sections, and grouting them in position. Each tunnel will require thousandsof perfectly designed, fibre-reinforced pieces, all of which will be manufactured on location.

Each machine will be operated by a staff of 17 people who will work in shifts to keep it functioning 24 hours a day, seven days a week. Over 100 personnel on the surface will assist them in handling logistics and ensuring that the tunnelling operation runs well.

According to HS2, construction has already resulted in the creation of jobs. HS2 has already helped to support approximately 16,000 jobs and 500 apprenticeships.

Transforge (UK) Ltd

Discover the comprehensive manufacturing component solutions for the tunnel boring industry.

Transforge (UK) Ltdhas become an established manufacturer of bored tunnel components for civil, mechanical and electrical engineers throughout the whole tunnel excavation and underground infrastructure tunnelling and fit-out process.

We’ve designed and manufactured a range of equipment and components for tunnelling projects including:

  • Utility cable and pipe supports
  • Slurry pipe brackets and accessories
  • Ventilation supports
  • Emergency walkway systems and platforms
  • Track, sleepers and accessories
  • Shaft Steelwork
  • Structural steelwork to BSEN1090 EXC 3. (Execution Class 3)


If you would like to get in touch about a tunnelling project or tunnelling components, please do not hesitate to contact us.


Tel: +44 (0)1733 249260

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