The Delhi Metro Rail Corporation (DMRC)on Wednesday successfully completed the first twin tunnels breakthrough under Phase-IV construction. The two tunnel boring machines (TBMs), Bhoomi and Srishti, emerged concurrently at Pulbangash Metro Station, marking the completion of the three km twin tunnels connecting Derawal Nagar to Pulbangash on the Janakpuri West – R K Ashram corridor (Magenta line Extension).

Sharing this information, DMRC said the event was graced by the presence of Dharmendra, Chief Secretary of Delhi and Dr. Vikas Kumar, MD, DMRC.

‘This is one of those rare occasions when two TBMs have emerged simultaneously after boring parallel tunnels. It is a major tunnelling feat as the engineers have to meticulously monitor the movement of two parallel machines.

‘Both TBMs were successfully retrieved at Pulbangash Metro Station on Wednesday, in just over 14 months, covering a length of approximately 2,997 metres, at an average rate of 8.2 metres per tunnel per day. This is also the longest tunneling drive (almost 3 km) in DMRC’s Phase IV works.

‘The tunnels were built at a depth of around 14-15 metres below the ground, passing through densely populated areas, including Rana Pratap Bagh and Punjabi Basti Colony.

They also passed beneath the Najafgarh drain, a sensitive section due to the uncertain structural condition of the drain.

‘Despite tunnelling in submerged water conditions, no damage was caused to any existing structures. The TBMs also had to bore through the under construction Ghanta Ghar station as retrieving them at that location was not feasible.