Second giant HS2 tunnel boring machine gets ready to start digging under Birmingham, United Kingdom. This is a A team of 90 specialist engineers have completed the assembly of HS2’s giant tunnel boring machine (TBM) which will start digging the second bore of the 3.5 mile Bromford Tunnel into Birmingham next year. In an assembly operation to move sections of the machine into a 12-metre deep launch pit, two 600 tonne cranes lifted the huge 125 tonne cutterhead into place at the front of the 125 m