Pictures have today been released of the tunnelling machines being build for the construction of HS2.

These two TBMs will spend around three years digging the longest and deepest HS2 tunnels from just inside the M25 to South Heath in Bucks.

At 10 miles long, these tunnels will be nearly the length of the UK part of the Channel Tunnel.

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With the pictures HS2 have released facts about the new equipment:

• The TBMs are 170m in length – nearly 5 times the length of a football pitch

• Each one weighs roughly 2000 tonnes – the equivalent of 340 African bush elephants

• When they start they will run non-stop for 3.5 years – only stopping for Christmas and Bank Holidays until the tunnels are complete

• The tunnels will go as deep as 80m below the ground – ensuring communities and countryside above are not impacted by the railway

• The size of the TBM cutterhead which will bore the tunnels is 10.26m, roughly the height of two giraffes standing on top of one another

• The internal diameter of the tunnels in which the trains will pass through will be 9.1m, slightly larger than two London buses stacked on top of one another

• The tunnels will be lined with concrete segments that will be 2m x 4m and weigh on average 8.5 tonnes each

• 112,000 of these concrete segments will be required to complete both tunnels

These machines have initially caused some local controversy due to HS2 wanting the public to vote to name the machines which will dig under parts of the Chilterns.

Mark Thurston, Chief Executive of HS2 Ltd, said: “The construction of HS2 is set to be an amazing opportunity to showcase global capability and innovation in the design and delivery of major infrastructure, and the Tunnel Boring Machines are one of the most fascinating aspects. Like mini cities, they will spend 24 hours a day, seven days a week boring under the Chilterns so that the homes and habitats above remain undisturbed.

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“This is just one of many ways in which HS2 is delivering on its responsibilities to our neighbours and the natural environment and, when complete, the new railway will play a key role in reducing transport carbon emissions and improving air quality for the next generation.”

The machines are being built by Herrenknecht in Germany.

Their names are being chosen now so they can be added to the machines during their manufacture, ready for when they emerge out of the factory.