India, Dec. 1 -- The Delhi Metro Rail Corporation (DMRC) has completed a technically challenging tunnelling task in its phase four expansion by constructing a tunnel beneath the operational Red Line at Pulbangash without disrupting train services. The tunnel is part of the Janakpuri West-" RK Ashram Marg extension of the Magenta Line and connects the Pulbangash and Sadar Bazar stretch.

According to the DMRC, trains on the busy Red Line continued to run throughout the operation, even as the tunnel boring machine (TBM) worked just below the elevated viaduct. The Red Line structure at the site sits on open foundations with a balanced cantilever span, making the task particularly sensitive, it stated, adding that engineers said tunnelling be...