Bengaluru Metro's Pink Line Achieves Milestone As TBM Tunga Prepares for Breakthrough Today

Bengaluru Metro's longest underground section is reaching a construction milestone with the Tunnel Boring Machine Tunga set to achieve its second breakthrough. This marks the 21st completed tunnelling assignment out of 24 on the 21.26-km Pink Line, connecting Kalena Agrahara to Nagavara via MG Road and Tannery Road, Deccan Herald reported.

The German-made Herrenknecht machine took 13 months to tunnel 1,260 meters between Venkatespura and Tannery Road after being launched on July 2021. Its second assignment, which began on October 31, 2022, involves boring through rock, soil, and a mixture of both between Venaktespura and KG Halli.

"The TBM has tunnelled its specified length and is currently engaged in core cutting, drilling holes and other works. It will emerge out of the KG Halli shaft on Wednesday," the daily quoted a well-placed source in Bangalore Metro Rail Corporation Limited (BMRCL) as saying.

Also, the BMRCL's Chief Public Relations Officer, B L Yashavanth Chavan, has confirmed about the development.

The Tunnel Boring Machine Tunga, part of Bengaluru Metro's Pink Line construction, bore 1,184.4 meters at an average rate of 2.99 meters per day, with its path comprising 40 per cent rock, 40 per cent soil, and 20 per cent both, the sources added.

Of the nine machines deployed for the 20.99 km Pink Line, seven have completed their tasks. Tunga, having finished two drives, will undergo a final drive from KG Halli to Nagavara in January 2024, while Bhadra's second drive will conclude by January 2023.

Bhadra's final drive is scheduled for March to July 2024. The Pink Line's 12 underground stations are progressing well, with completion percentages ranging from 65 per cent to 90 per cent, the report claimed.