Meet Crossrails giant tunnelling machines

Crossrail will use eight tunnel boring machines (TBMs) to construct the new tunnels under London. These huge machines will work 24 hours a day beneath the streets of London, excavating large volumes of ground and erecting the concrete tunnel lining. Each machine has a rotating cutter head at the front, and a series of trailers behind, housing all the mechanical and electrical equipment required for the excavation of material. To construct the 42km of tunnel required for Crossrail the tunnel bo