Tunnel boring machine (TBM) ‘Divya’ on Tuesday began tunnelling from the Victoria Memorial metro station as part of the Joka-Esplanade corridor, officials said.
The Joka-Esplanade corridor, also known as the Purple Line, will connect southwestern parts of Kolkata with the city’s central areas.
The corridor is being constructed using two TBMs, ‘Durga’ and ‘Divya’, which are engaged in excavating a 2.65-km-long twin-tube tunnel between Kidderpore and Park Street.
‘Durga’ reached the Victoria Memorial station after excavating the tunnel from the Kidderpore side, while ‘Divya’ has been working on the tunnel towards Joka.
The TBMs are operating around 17 metres below ground level in the Kidderpore area. While ‘Durga’ is tunnelling towards Park Street, ‘Divya’ is being used for excavation on the Joka-bound line.
The two next-generation TBMs, manufactured in Chennai, are around 95 metres long and weigh approximately 600 tonnes each. They can excavate at a rate of nearly 80 mm per minute, Metro Railway officials said.
The machines are equipped with advanced safety features, including inflatable seals, pressure transducers, tail-skin grease lines and backup tail-skin grease pumps, designed to suit local geological conditions.
Tunnelling by ‘Durga’ is expected to be completed by December 2026, while ‘Divya’ is scheduled to achieve its breakthrough by March 2027, officials said.
(PTI)
