Tunnelling in the city has been a mix of a few fairly smooth journeys and some complicated ones so far.
| Photo Credit: S.R. RAGHUNATHAN
Nearly 35% of Chennai Metro Rail’s underground network has been built for the upcoming ₹63,246 crore phase II project.
Across the three corridors—Madhavaram to SIPCOT (corridor 3), Light House to Poonamallee (corridor 4) and Madhavaram to Sholinganallur (corridor 5) which constitute the 118.9 km phase II project, Chennai Metro Rail has to bore for a total length of 69.05 km.
According to officials of Chennai Metro Rail Limited (CMRL), of the 69.05 km of tunnel length to be created in all three corridors of the phase II project, 24.2 km of tunnels have been built.
The Madhavaram-SIPCOT corridor makes for the majority of the underground network; in this corridor alone, CMRL has to build tunnels for a length of 43.04 km and at present, 16.2 km has been completed. In the Poonamallee-Light House corridor, of 16.29 km to be tunnelled, 7.56 km has been finished. In the Madhavaram-Sholinganallur corridor, the underground network is only for 9.2 km but since the work was delayed due to tender issues, only 0.48 km of tunnel has been built so far.
Officials said, the underground construction is gradually picking up pace and this month alone, three tunnels—between Greenways Road and Mandaveli, Royapettah and Dr. Radhakrishnan Salai and Panagal Park to Kodambakkam—finished their journeys.
In the coming months, quite a few tunnel boring machines (TBM) will finish their journeys and achieve breakthroughs in locations including Perambur, Moolakadai, Kellys, Kilpauk and Thirumayilai. TBMs will also be launched in various sites including Thiruvanmiyur, Chetpet, Perambur Barracks Road and Kolathur.
Tunnelling in the city has been a mix of a few fairly smooth journeys and some complicated ones so far. In some of the areas like T. Nagar, Kodambakkam, Perambur, Adyar and Chetpet, the TBMs had to bore under flyovers, railway tracks and waterbodies. This aside, between Light House to Thirumayilai, the TBMs encountered tough geological conditions and their parts had to be replaced numerous times.
Published – October 23, 2025 05:30 am IST
