Main features of the TBM Machine type Telescopic double-shield TBM (made by Mitsubishi) Boring diameter 4.88m Cutters 43cm (back-load type) Number of disc cutters 32 Type of cutterhead drive Electric drive with variable speed (frequency variation) Cutterhead speed 0-9 rev/min (electrical variable rotation speed) Cutterhead drive power 6 x 250kW=1500kW Boring stoke: main thrust 1300mm Auxiliary thrust 2200mm Mucking system Through belt conveyor Machine weight (total) Approx. 450t Total length of TBM (with back-up) 115m