Chennai Metro Rail Limited (CMRL) has achieved a significant milestone in its Phase II expansion by completing the tunnel between Ayanavaram and Perambur stations. On May 13, 2025, the tunnel boring machine (TBM) Kalvarayan completed its 867-meter drive, surfacing at the Perambur south shaft. This marks the 11th tunnel breakthrough in the Phase II project and the seventh under the contract executed by Tata Projects Limited.The tunneling operation faced considerable challenges, including navigating beneath active railway tracks at Perambur station and through densely populated residential areas. Engineers also had to manage over 32 borewells along the route, ensuring uninterrupted water supply by providing alternate sources. Advanced instrumentation and continuous monitoring were employed to maintain ground stability and minimize surface disruptions.
This breakthrough is part of the initial 9 km underground stretch of Corridor 3, extending from Madhavaram Milk Colony to Kellys. Despite earlier delays due to tendering issues and water seepage at the Perambur station site, CMRL remains on track to complete the entire Phase II project, encompassing over 118 km of new metro lines, by July 2028.