CHENNAI: Chennai Metro Rail Limited (CMRL) has achieved a major milestone in its Phase II expansion, completing the city’s ‘longest twin tunnel stretch’ between Panagal Park and Kodambakkam ramp with the breakthrough of its tunnel boring machine ‘Pelican’ on Wednesday.
The machine’s arrival at Kodambakkam marks the second and final breakthrough for the corridor segment, following a parallel drive completed by TBM ‘Peacock’ on July 23. Together, the two drives complete the up and down tunnels for this critical link under corridor-4, package UG-2 of the metro project.
The 2.08-km drive, which began on March 1, 2024, and transitioned into full operation by mid-May, was completed over 594 days, making it the longest tunnel delivered in Phase II so far. It passes beneath some of Chennai’s most congested urban infrastructure, reaching a maximum depth of 31.4 metres below railway tracks at Kodambakkam, one of the deepest points on the alignment.
Senior CMRL officials, including director (projects) T Archunan were present at the breakthrough. Engineers navigated fractured and mixed geological strata, multi-storey buildings, and key transport crossings – including Indian Railways infrastructure and two active flyovers – while maintaining structural integrity. The drive involved a tight S-curve with a 206-metre radius and the steepest tunnel gradient in the entire project at +2.581%.
IGBC platinum certification
CMRL has secured the Indian Green Building Council Platinum certification for its Nandanam headquarters, in recognition of its efforts towards sustainability, a release said.
The award was handed over to CMRL MD M A Siddique, director (projects) T Archunan, and chief general manager (planning & design) Rekha Prakash by CN Raghavendran, managing director of CR Narayana Rao, alongside IGBC Chennai Chapter chairman Mahesh Anand and co-chair Sriram Iyer.
The headquarters project preserved 69 mature trees and achieved sustainable landscaping over 79% of the site. Potable water consumption has fallen by more than 31% through low-flow fixtures, while 100% on-site wastewater treatment now meets 94% of flushing and irrigation needs.