The previous record of 273 metres was set by Tunnel Boring Machine (TBM) ‘Urja’ between Cantonment and Pottery Town in Bengaluru, in May 2022.
| Photo Credit: File photo
Namma Metro’s Tunnel Boring Machine (TBM) ‘Tunga’ has set a new record. In July, ‘Tunga’ tunnelled through a remarkable 308 metres, surpassing the previous record of 273 metres set by TBM ‘Urja’ in May 2022, according to Bangalore Metro Rail Corporation Limited (BMRCL).
According to BMRCL, “In July 2024, BMRCL achieved its maximum tunnelling to date. The TBM ‘Tunga’ completed 308 metres of tunnelling between K.G. Halli and the Nagawara retrieval shaft. This surpasses the previous record of 273 metres set by TBM ‘Urja’ between Cantonment and Pottery Town in May 2022.”
BMRCL has deployed nine tunnel boring machines (TBMs) for construction of Namma Metro lines across Bengaluru. Seven of these machines — Urja, Varada, Avni, Lavi, Vindhya, Vamika, and Rudra — have successfully completed their tasks. The eighth TBM, Tunga, commenced its final drive from K.G. Halli to Nagavara, covering 935 metres, on February 2, 2024 for the Pink Line. The ninth TBM, Bhadra, is currently working on its final assignment, a 939-metre northbound tunnel from K.G. Halli to Nagavara.
In July, tunneling operations with TBM Tunga were halted due to a sinkhole that appeared on the road surface in K.G. Halli. Officials reported that the sinkhole, measuring approximately 2.5-3 metres in width and 3 metres in depth, was probably caused by an air pocket. After the sinkhole was repaired, TBM Tunga resumed tunnelling.
Officials anticipate that TBM Tunga will surface at Nagavara, the terminal station of the Pink Line, on October 30. Having commenced its final drive on February 3, Tunga has already tunnelled 469 metres of the total 938-metre target.
Officials expect Pink Line of Namma Metro to open in 2025.
Progress on this stretch has experienced considerable delays over the years due to various factors, including tender cancellations due to high bids, changes in alignment before final approval, challenges with land acquisition, and other obstacles. Officials now expect that the entire stretch may be completed and opened in 2025.
