TBM ‘Divya’ Breaks Through on Kolkata Metro’s Purple Line, Completes Second Khidderpore–Victoria Tunnel
Kolkata Metro achieved a major engineering milestone on August 11, 2026, with the successful breakthrough of Tunnel Boring Machine (TBM) ‘Divya’ at Victoria Metro Station. The breakthrough marks the completion of the second underground tunnel between Khidderpore and Victoria on the Joka–Esplanade Metro Corridor, also known as the Purple Line.
TBM ‘Divya’ completed a 1.72-kilometre-long tunnel drive from Khidderpore to Victoria, taking the construction of the underground section of the corridor a significant step forward. The latest achievement is expected to support the ongoing development of the Joka–Esplanade corridor and strengthen Kolkata’s urban mass rapid transit network.
TBM ‘Divya’ Completes 1.72-Km Tunnel Drive
The breakthrough was achieved at Victoria Metro Station after TBM ‘Divya’ successfully completed its tunnelling operation from Khidderpore. The machine has now finished the second tunnel between the two stations.
The TBM is a 6.60-metre-diameter Earth Pressure Balance (EPB) machine, specially suited for tunnelling through Kolkata’s challenging geological conditions. The city’s soft soil and high groundwater levels require specialised tunnelling technology and close monitoring during underground construction.
With a length of around 95 metres and an approximate weight of 600 tonnes, TBM ‘Divya’ is a large-scale machine designed to undertake heavy underground construction work in a densely populated urban environment.
Advanced Tunnel Construction Technology
The tunnel constructed by TBM ‘Divya’ has been lined using M50-grade precast concrete segments. These segments are installed progressively behind the TBM as excavation advances, creating the permanent structural lining of the underground tunnel.
The use of an EPB-type TBM enables excavation and ground-pressure management to be carried out simultaneously. This is particularly important in Kolkata, where underground construction has to be undertaken while managing soft ground and significant groundwater conditions.
The tunnelling operation was carried out with a strong focus on safety, construction quality and precision. Another key challenge was maintaining normal surface traffic and day-to-day activities while major underground construction was taking place beneath a densely populated part of Kolkata.
Second Tunnel Completed Between Khidderpore and Victoria
The breakthrough of ‘Divya’ follows the successful breakthrough of another TBM, ‘Durga’, on July 10, 2026. TBM ‘Durga’ completed the first underground tunnel between Khidderpore and Victoria on the Purple Line.
With both TBMs now having achieved breakthroughs, the two underground tunnels connecting the two stations have been completed. This represents an important milestone for the construction of the Joka–Esplanade Metro Corridor.
The successful operations of ‘Divya’ and ‘Durga’ demonstrate the engineering capabilities and planning required for constructing underground metro infrastructure in one of India’s most densely populated metropolitan regions.
Boost to Kolkata’s Metro Expansion
The Joka–Esplanade Metro Corridor is an important addition to Kolkata’s expanding metro network. The completion of the two tunnels between Khidderpore and Victoria will contribute to the progress of the underground portion of the corridor.
The latest breakthrough is also a reflection of coordinated efforts by the engineering, tunnelling and project teams involved in the construction. Careful planning, advanced machinery and stringent safety and quality measures were crucial to completing the 1.72-km tunnel drive successfully.
The August 11 breakthrough of TBM ‘Divya’ therefore marks more than the completion of another tunnel drive. It represents another significant step towards advancing the Joka–Esplanade Metro Corridor and improving Kolkata’s urban public transport infrastructure.
