In a significant stride for its ambitious Phase 2 expansion, the Chennai Metro Rail Limited (CMRL) has successfully completed a crucial underground tunnelling segment. The Tunnel Boring Machine (TBM) named 'Melagiri' achieved a breakthrough at the Perambur metro (south) shaft on Corridor-3, marking a major engineering feat beneath one of the city's complex zones.
Navigating a Challenging Underground Maze
This latest accomplishment adds an 861-metre long underground link to the expanding network of Corridor-3. The breakthrough, which occurred on December 31, 2025, represents the eighth such milestone completed by Tata Projects Limited under its specific contract package, known as TU-01. It underscores the steady progress being made on the city's largest metro project, which spans a total of 118.9 kilometres in its second phase.
Officials highlighted that the Ayanavaram to Perambur stretch is among the most difficult sections of the entire alignment. The tunnelling work had to be executed with extreme precision due to dense residential neighbourhoods, existing railway infrastructure, and severely limited working space above ground. The path of the tunnel runs directly below thickly populated areas, necessitating continuous monitoring to prevent ground settlement and ensure the safety of buildings and utilities.
Overcoming Groundwater and Safety Hurdles
A unique challenge encountered along this route was the presence of over 32 borewells. CMRL engineers conducted detailed surveys and implemented specific mitigation measures to address potential groundwater-related issues that could have arisen during the boring process. The focus on safety was paramount throughout the operation.
Strict safety protocols, real-time monitoring systems, and close coordination with multiple civic agencies were employed to ensure the breakthrough was completed without any incidents. This careful approach was especially critical given the sensitivity of working under such a densely built-up and infrastructurally congested part of Chennai.
Steady Progress on a Massive Project
With the success of TBM Melagiri, CMRL has now completed a total of 19 TBM breakthroughs as part of the Phase 2 project. The overall phase includes a mix of both elevated and underground corridors designed to significantly enhance connectivity across Chennai.
This milestone not only strengthens the progress on Corridor-3 but also demonstrates the technical capability required to execute large-scale urban infrastructure projects in challenging environments. The continued advancement of Phase 2 is a critical step towards alleviating the city's traffic congestion and providing a modern, efficient public transport system for its residents.
