2021: the year of tunnelling

High Speed 2

What will 2021 bring? For High Speed 2 the new year should see the start of tunnelling.

The first tunnel drive will start at the M25 as work gets underway to dig a 10-mile twin bore, the longest on the HS2 route, under the Chiltern hills.

Two tunnel boring machines, Florence and Cecilia, have arrived at the launch site after being shipped over from TBM manufacturer Herrenknecht in Germany. Delivering two 170-metre-long machines fully assembled is not realistic and so it has taken 300 separate shipments over the course of two months. But all parts have now been delivered to the Chiltern tunnel launch site, to the west of London just inside the M25, allowing HS2’s main works contractor Align – a joint venture formed of Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick – to get out the instruction manual and start bolting the components together.

Designed for the mix of chalk and flints under the Chilterns, the two identical TBMs will dig separate tunnels for north and southbound trains, with Florence set to launch first and Cecilia to go next a few weeks behind.

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