TBM Kaveri records Tunnel Breakthrough at KMC Station for Chennai Metro Phase 2

Chennai, India (Rail & Metro Today): Chennai Metro Rail Limited (CMRL) achieved another major tunnelling milestone in Chennai Metro Phase-II on Tuesday, with Tunnel Boring Machine (TBM) ‘Kaveri’ breaking through at Kilpauk Medical College (KMC) Station after completing a 685-metre underground drive from Chetpet.

The downline tunnelling between Chetpet and KMC was completed in 252 days, marking another significant step in the construction of Corridor-3 under the Phase-II project.

TBM Navigates Challenging Underground Conditions

The tunnelling operation presented several engineering challenges, with TBM Kaveri passing beneath five live Southern Railway tracks, the Chetpet Eco Park lake and buildings located within the Kilpauk Medical College campus.

According to CMRL, the TBM passed beneath the railway tracks with an approximate overburden of 18 metres. The tunnel sections beneath the lake and KMC buildings were constructed at depths corresponding to an overburden of approximately 21 to 26 metres.

The drive also required careful tunnelling near the existing Phase-I Metro tunnels. A minimum clearance of 6.1 metres was maintained between the Phase-I and Phase-II tunnels, adding to the engineering complexity of the underground works.

The tunnelling work was executed by Larsen & Toubro (L&T). CMRL said the drive was completed without any major ground settlement or adverse impact on existing infrastructure.

During the operation, 10 cutterhead interventions were carried out to support the tunnelling process.

Two TBMs Deployed Between Chetpet and KMC

The Chetpet–KMC underground section was constructed using two TBMs. ‘Tamarabharani’ was deployed for the upline, while ‘Kaveri’ undertook the downline.

Tamarabharani achieved its breakthrough on November 26, 2025, completing the upline tunnelling operation. Kaveri has now completed the corresponding downline drive, marking the completion of tunnelling between the two stations.

CMRL said the latest breakthrough is the ninth TBM breakthrough under the TU02 contract, reflecting continued progress in the underground construction works of Chennai Metro Phase-II.

Another Milestone for Corridor-3

The Chetpet–KMC section forms part of Corridor-3 of Chennai Metro Phase-II. The deployment of the two TBMs had marked the beginning of tunnelling between the stations, while the latest breakthrough completes the downline tunnel.

The successful completion of the 685-metre drive is particularly significant because of the multiple sensitive structures and existing transport infrastructure encountered along the alignment. Maintaining adequate clearance from operational railway tracks, the existing Metro tunnels and surface structures required careful planning and execution.

CMRL Managing Director Ashish Chatterjee, Director (Projects) T. Archunan, along with senior officials from CMRL, consultants and Larsen & Toubro, witnessed the breakthrough ceremony at KMC Station.

The latest achievement adds to the ongoing progress of Chennai Metro Phase-II, where extensive underground construction is being undertaken to expand the city's rapid transit network and improve connectivity across key parts of Chennai.