On November 27th, the international JV of Impregilo (Italy) and NCC (Sweden) successfully finished re-excavation of the second 800m long tube of Line 1 of the St. Petersburg Metro, Russia. The breakthrough of the 7.4m diameter Voest Alpine Polyshield TBM sees construction completed on one of the most technologically demanding sections of soft ground, segmentally lined twin tube metro tunnel ever undertaken.
