The construction of HS2s longest tunnels - stretching for 10 miles under the Chilterns - passed a key milestone this week with mining completed for 19 out of 38 emergency cross-passages linking the northbound and southbound tunnels.
(Permalink) Chiltern Tunnel HS2

HS2 this week launched 'Cecilia' - the second of two enormous 2,000 tonne tunnelling machines that will excavate the ten mile long tunnels beneath the Chiltern hills just outside London. The first machine “ 'Florence' “ was launched just over a month ago.
(Permalink) Chiltern Tunnel HS2 TBM