Thirteen Tunnel Boring Machines (TBMs) are to be used to complete 14.45km of the 29.83km Delhi Metro phase two.
The first two of these TBMs have been refurbished following their work on Phase I and final testing has been carried out this week.
These will be lowered into the ground by the end of this month and will start tunneling from Malviya Nagar to Hauz Khas in south Delhi. A 18m deep shaft is being sunk at Malviya Nagar.
The remainder of the machines required will be a mixture of new and refurbished plant with German company Herrenknecht providing the new machines.
Three TBMs will be used to build the Airport Express Line which will connect the heart of the city to the international airport. This 19.5 km distance will be covered by the Metro trains in 16 minutes.
To ensure safety of buildings above the TBMs, influence zone is being calculated and study for soil settlement and building conditions is being done.
Work on the elevated and cut-and-fill sections of the metro have already begun and it is anticipated that Phase II will be completed before the Commonwealth Games in New Delhi in October 2010.