Chennai Metro Rail Limited achieved a major milestone for Chennai Metro Phase II on Thursday as TBM Adyar completed its drive. The Downline Tunnel Boring Machine broke through at RK Salai Station, marking CMRL’s third consecutive breakthrough in three days. Consequently, Larsen & Toubro Limited advanced tunnelling operations across Corridor 3 and Corridor 5.
Three TBM breakthroughs in three days accelerate underground works
The tunnelling streak began when Corridor 3 TBM Kaveri reached KMC Station on September 29. Furthermore, Corridor 5 TBM Maruthan achieved its breakthrough at Villivakkam Station on September 30. Finally, TBM Adyar completed its 915-metre drive at RK Salai Station on October 1.
| TBM Name | Corridor | Destination Station | Breakthrough Date |
| Kaveri | Corridor 3 (Downline) | KMC Station | September 29, 2026 |
| Maruthan | Corridor 5 (Downline) | Villivakkam Station | September 30, 2026 |
| Adyar | Corridor 3 (Downline) | RK Salai Station | October 01, 2026 |
Contractors advance 12-km underground corridor between Kellys and Taramani
Additionally, Larsen & Toubro operates eight TBMs along the 12-km underground section of Corridor 3. Tunnelling between Royapettah and RK Salai began in September 2024 using TBMs Bhavani and Adyar. Meanwhile, Upline TBM Bhavani completed its drive on October 13, 2025.
TBM Adyar started driving on December 29, 2025, and finished the drive in 277 days. Thus, this latest success marks the 10th TBM breakthrough under contract TU02 for Chennai Metro Phase II.
