Larsen & Toubro’s (L&T) tunnel boring machine (TBM) Adyar (S-1326A) has achieved its first breakthrough at Adyar Junction for Package TU-02 on Chennai Metro Phase 2’s Line 3. This milestone marks the fourth breakthrough in the 12 km tunnel stretch between Kellys and Taramani Road Junction stations. The 116.1 km Phase 2 project aims to improve connectivity across Chennai, with Line 3 spanning 45.8 km and 49 stations—20 elevated and 29 underground. A Key Milestone for Chennai Metro TBM Adyar, a 100m-long Herrenknecht earth pressure balance (EPB) machine, began its assignment at Greenways Road Station in April 2023. Over 22 months, it navigated complex geological conditions, including constructing a 300m tunnel under the Adyar River, before breaking through at Adyar Junction. L&T has deployed eight TBMs for twin tunnel construction under Package TU-02, which involves building 24 km of tunnels. Project Background & Scope L&T secured Package TU-02 from Chennai Metro Rail Ltd. (CMRL) in May 2021 for Rs. 23.85 billion ($286 million), with a 42-month deadline. The contract covers: Twin tunnel construction between Kellys and Taramani Road Junction Diaphragm walls and entry/exit structures for Chetpet, Royapettah Government Hospital, and Thiruvanmiyur stations Partial diaphragm wall construction at Greenways Road Station Chennai Metro’s Progress on Line 3 With TBM Adyar’s breakthrough, 10 tunnel breakthroughs have been completed on Line 3. Other notable breakthroughs include: Siruvani (DZ1040) – Sterling Road (703m) – August 2024 Kaveri (S-1327A) – Adyar Junction (1,228m) – September 2024 Palar (DZ1041) – Sterling Road (700m) – October 2024 Pushing Forward As Chennai Metro Phase 2 progresses, each breakthrough brings the city closer to a seamless urban transit system. A CMRL official noted, “These milestones reflect the dedication of our teams in overcoming challenging tunneling conditions to enhance Chennai’s metro connectivity.” With more breakthroughs expected in the coming months, Chennai Metro continues to shape the city's urban transport landscape.