Chennai Metro Rail Limited (CMRL) has launched a tunnel boring machine (TBM) for the Panagal Park–Boat Club stretch of Corridor 4, marking a fresh phase of underground work under the city’s Phase 2 expansion.
Phase 2 comprises three corridors covering 118.9 km with 128 stations.
Corridor 4 runs 26.1 km from Light House to Poonamallee Bypass and features a key underground portion between Light House at Marina Beach and Kodambakkam Flyover, split into two packages, UG-01 and UG-02.
Four TBMs with an excavated diameter of 6.67 m are being used to build about 16 km of twin tunnels on this corridor.
The latest launch, for package UG-02, took place on 12 December 2025 for the drive between Panagal Park and Boat Club.
The TBM “Peacock” had earlier completed a 2 km drive from Panagal Park to the Kodambakkam ramp retrieval shaft near Meenakshi College on Arcot Road, delivering the first breakthrough on the underground stretch of Corridor 4 on 23 July 2025.
That drive involved tunnelling below live Indian Railways tracks.
After the breakthrough, the machine was dismantled at Kodambakkam, taken back to Panagal Park and reassembled for a second drive of 1.89 km towards Boat Club Station.
It is the first TBM to begin work on one of the twin tunnels in this section.
The current drive includes tunnelling beneath operational Phase 1 metro tunnels near Nandanam Metro Station, with the alignment reaching depths of up to 30.2m below ground.
TBM Peacock, launched on the down line of Corridor 4, will move from Panagal Park towards Nandanam and on to the retrieval shaft at Boat Club Station.
CMRL expects to complete this drive by November 2026.
