CHENNAI: Chennai Metro Rail Ltd (CMRL) has completed a 1.08-km underground tunnel drive beneath a densely populated residential neighbourhood in north Chennai, overcoming challenging geological conditions. Tunnel boring machine Kurinji emerged at Srinivasa Nagar on Friday after almost a year underground.
The machine began its drive from Kolathur station on November 27, 2025, and reached the Srinivasa Nagar North Shaft on its 351st day.
The drive involved negotiating a sharp curve with a 230-metre radius through varying geological conditions, ranging from soil and weathered rock to hard rock. The machine also passed beneath or near more than 70 borewells and open wells in the densely populated residential area, according to CMRL.
Kurinji is one of four machines, along with Mullai, Marutham and Neithal, digging the 5.8-km underground section of Corridor 5, part of the second phase of Chennai Metro.
The corridor is 47 km long, of which 41.2 km is elevated. The underground stretch has five stations and two ramps. Tata Projects is executing the work with funding from the Japan International Cooperation Agency (JICA).
CMRL described Kurinji’s arrival as the first tunnel breakthrough on Package C5UG06, which involved negotiating a sharp curve beneath heavily built-up areas.
The release also cited 3.78 km of subsequent tunnel completion on the corridor.
Ashish Chatterjee, CMRL managing director, attended the breakthrough along with T Archunan, director of projects, and senior executives from Tata Projects and the project’s general consultants.
Alstom starts production of 32 driverless trains
Chennai French rolling-stock manufacturer Alstom has started production of 32 three-car driverless trainsets for Chennai Metro Rail’s Phase II project at its Sri City facility in Andhra Pradesh, under a $135 million (about `1,470 crore) contract awarded in 2025.
The new trains will be configured for Grade of Automation 4 (GoA4), the highest level of railway automation, which allows fully driverless operations. With a maximum operating speed of 80 kmph, each three-car trainset can accommodate up to 900 passengers, according to a statement from Alstom.
The trains will also have regenerative braking systems and cybersecurity measures. Alstom had completed an earlier $102 million (about `1,110 crore) contract for 36 trainsets, comprising 108 cars, for Corridor 4 in October.
The 26-km corridor, connecting Poonamallee Bypass with Light House through 28 stations, has begun operations partially in the elevated stretch from Vadapalani to Poonamallee Bypass. Chennai Metro’s Phase II project spans about 119 km across three corridors, with more than 76 km of elevated tracks and 43 km underground.
