Chennai Metro Rail Limited (CMRL) has reached a significant milestone in its Phase 2 project with the first breakthrough of Tunnel Boring Machine (TBM) “Kurinji” at Kolathur Station North Shaft on August 21, 2025.The TBM started its drive on February 20, 2025, from Kolathur Ramp and successfully completed a 246-metre tunnel. The tunnelling process faced several challenges, including low overburden, steep gradients, and heavy traffic along the Inner Ring Road.
This breakthrough is the first in Corridor 5’s underground section, which covers 5.8 km and includes five stations and two ramps. The tunnelling work is being carried out by Tata Projects Ltd., with funding support from the Japan International Cooperation Agency (JICA).
CMRL officials stated that this achievement reflects their commitment to providing safe, sustainable, and efficient urban transport for the city of Chennai.