The tunnel boring machine (TBM) Helen achieved a major feat on Wednesday when it broke the diaphragm wall at the City Railway Station underground (UG) Station off Magadi Road thereby completing one of the twin tunnels on the East-West corridor of Namma Metro Phase 1.

Bangalore Metro Rail Corporation Ltd. (BMRCL), in a release, said the fourth and final breakthrough on the ‘down’ line was achieved at 10.30 a.m. after Helen burrowed 229 metres of tunnel from the pocket track, off City Railway Station to the City Railway Station UG station.

The same TBM would be deployed to burrow the ‘up’ track tunnel from City Railway Station UG station towards the pocket track shortly, completion of which would make both the tunnels ready for track laying and other related activities.

Wednesday’s breakthrough has completed one of the twin tunnels of the 4.8 -m underground network, between BRV Parade Grounds and Magadi Road on the East-West corridor of Namma Metro Phase 1. Tunnelling from the Pocket Track (last stretch) had commenced on November 1, 2013. BMRCL has said the remaining portion of the ‘up’ tunnel could be completed in about 70 days. thereby completing the entire tunnel network of the East-West Corridor


Third tunnel boring machine deployed August 27, 2012

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