Kolkata7 minutes agoAuthor: Tirthankar Das
Tunnel Boring Machine (TBM) Durga achieved a major milestone on Friday by making its breakthrough into the under-construction Victoria Memorial Metro Station, exactly one year after beginning tunnel excavation from Kidderpore on July 10, 2025.
‘Durga’ completes first tunnel breakthrough successfully
The breakthrough marks the successful completion of the first underground tunnel drive of the Joka–Esplanade Purple Line. In tunnelling, a breakthrough refers to the moment when a TBM cuts through the final barrier of rock, soil, or concrete and emerges into the receiving shaft or underground station.
Breakthrough marks major engineering construction milestone
TBM Durga completed the 1.7-km tunnel between Kidderpore and Victoria Memorial. The machine will now be dismantled, serviced, and relaunched for the second phase of tunnelling from Victoria Memorial to Park Street, covering another 900 metres.
Meanwhile, its sister machine, TBM Divya, which is constructing the parallel tunnel, is expected to complete its first tunnel drive by the first week of August.
Machine prepares for second tunnelling phase
The two TBMs, assembled in Tamil Nadu using components imported from Germany’s Herrenknecht, are among India’s first major Make-in-India tunnel boring machines. Each machine is about 95 metres long, weighs nearly 600 tonnes, and is equipped with advanced safety systems, including inflatable seals, pressure transducers, and tail skin grease (TSG) backup pumps.
‘Divya’ expected finish tunnelling next month
The 14-km Joka–Esplanade Metro corridor currently has an 8-km operational elevated section between Joka and Majerhat. Construction is underway on the remaining elevated station at Mominpore, while underground work is progressing toward Esplanade. Officials said the Victoria Memorial breakthrough is a key step in accelerating the long-delayed Purple Line project, which has faced repeated setbacks due to land acquisition issues.
