HS2 launches giant tunnelling machine at Chiltern Hills site

Chief executive Mark Thurston described the start of work to dig a 10-mile tunnel under the Chiltern Hills as "a major step forward".

The 558ft (170m) long tunnel boring machine (TMB) was launched at HS2's site near Maple Cross, by the M25 motorway, on Thursday.

It will work non-stop for three years and is one of 10 TBMs being deployed between London and the West Midlands for Phase 1 of the high-speed railway.

The tunnelling machine will dig 10 miles through the Chiltern Hills. Credit: PA

Transport Secretary Grant Shapps said the launch of the first TBM at West Hyde is "a landmark moment for the project".

He went on: "The work has truly begun on taking HS2 northwards.

"The tunnels these machines dig will ensure the benefits of our new high-capacity, high-speed railway run to the great cities of the North and Midlands, forging stronger connections in our country, boosting connectivity and skills opportunities, and transforming our transport links."

HS2 tunnelling site in West Hyde. Credit: PA

A worker in the control room of the tunnelling machine named after Florence Nightingale. Credit: PA

The TBM launched on Thursday - the largest ever used on a UK rail project - has been named Florence after Florence Nightingale, the founder of modern nursing who spent many years in Buckinghamshire.

It will be joined by a second, identical machine, enabling separate tunnels for north and southbound trains to be dug.

The tunnels will reach depths of up to 262ft (80m) below ground to reduce the impact of high-speed trains on communities and countryside.

The 2,000-tonne machines will operate as self-contained factories with a crew of 17 people working 12-hour shifts to keep them running continuously.

In addition to digging, the TBMs will line the tunnel walls with concrete segments as they move forward at a speed of 49 feet (15m) per day.

They will also convert the material they dig out into slurry, which will be pumped out the tunnels and used for landscaping.

The site pictured is in West Hyde near Maple Cross, Hertfordshire, and the tunnel will be dug through Buckinghamshire. Credit: PA

Specialist firm Herrenknecht built the machines at its factory in south-west Germany at a cost of tens of millions of pounds each.

The TBMs were transported to the UK in more than 300 separate shipments last year before being reassembled.

They are designed specifically for the mixture of chalk and flints under the Chilterns.

Digging the tunnels is part of a £1.6 billion contract awarded to Align, a joint venture formed of infrastructure companies Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick.

Credit: PA

HS2 will be extended from Birmingham to Crewe in Phase 2a, with Phase 2b planned to run from Crewe to Manchester, and from Birmingham to Leeds.

There is major concern about the cost and environmental impact of building the high-speed railway.

The Government-commissioned Oakervee Review warned in 2018 that the final bill could reach £106 billion (at 2019 prices) due to it running tens of billions of pounds over budget.

Meanwhile, environmental activists sprayed pink paint on to the London office of HS2 last week, in protest at the CO2 emissions created by the construction work.

Credit: PA

In an interview with the PA news agency, Mark Thurston, chief executive of HS2 Ltd, said: "HS2 is a way of getting investment into the economy when we know the economy is struggling on the back of the pandemic.

"I would hope the country gets behind what is a national endeavour and takes pride in the fact that this is creating jobs for British people."

Mr Thurston said more than 16,000 jobs and 500 apprenticeships are already being supported by the work.