Mahalaya is still 72 days away, but ‘Durga’ has already begun her journey—not from the skies, but from underground. Here, ‘Durga’ refers not to the goddess, but to a massive tunnel boring machine (TBM), named after her, that has started digging tunnels for the Kolkata Metro’s Purple Line.
On Thursday, the machine began its work from Kidderpore for the 5 km underground stretch between Mominpur and Esplanade. This marks a major step forward for the Purple Line, a 14 km metro route from Joka to Esplanade.
Metro Railway’s General Manager, P Uday Kumar Reddy, called it a historic moment and launched the machine by pressing a button. The digging began right below the 236-year-old St Thomas’ Boys’ School at Kidderpore. Another similar machine, named ‘Divya’, is being assembled and will start digging a month later, keeping a 150-metre distance from ‘Durga’.
Both machines will first reach the Victoria Memorial after digging 1.7 km. After that, they will be moved to the Victoria Metro station area to dig another 950 metres to Park Street. The final 640 metres to Esplanade will be built using a different method (called cut-and-cover) without tunnel boring machines.
The tunneling project is expected to reach Victoria Memorial by May 2026 and Park Street by December 2026, according to Vipin Kumar from Rail Vikas Nigam Ltd (RVNL), which is handling the project. A small puja (prayer ceremony) was held to mark the start of work, attended by RVNL and Metro officials.
Currently, the Purple Line operates on an elevated 8 km route from Joka to Majerhat. It will go underground near Ekbalpore, close to the Mominpur station.
The machine, weighing 650 tonnes, travelled all the way from Tamil Nadu to Kolkata earlier this year. Built by Herrenknecht in Tamil Nadu, ‘Durga’ has an outer diameter of 6.6 meters and was lowered into the ground in March.
TBMs are traditionally given female names, following a mining tradition that goes back centuries. Since Kolkata is the land of Maa Durga, naming the machine ‘Durga’ seemed fitting. The second machine is called ‘Divya’, meaning “divine” in Sanskrit.
Officials are taking extra care during this work to avoid past issues, like the tunnel collapse in Bowbazar during East-West Metro construction. On another metro project—the Orange Line—there is still a roadblock at Chingrighata. Metro officials said the Railway Minister has urged the state government to help move that project forward.
