TBM Karen will excavate the second bore of the 4.5-mile Euston Tunnel.

A 271.5-tonne tunnel boring machine has started excavating a 2.2km tunnel to carry electricity beneath the River Thames.

Nearly 200 metres long and weighing over a thousand tonnes, HS2’s final tunnel boring machine is an underground factory digging a railway to Euston.

HS2 has officially commenced excavation work of the final tunnel bore on the 140-mile railway between central London and the West Midlands.

Chinese engineers have pulled off a stunning rescue, saving a tunnel boring machine (TBM) stuck 177 feet underground beneath ...