Chennai Metro Phase 2 tunnelling has moved into a fresh underground push, with Tunnel Boring Machine (TBM) “Peacock” starting its next drive on Corridor 4.

This is reported by the railway transport news portal Railway Supply.

Chennai Metro Phase 2 tunnelling update: TBM Peacock launch
Photo: CMRL

According to a CMRL press release, the TBM was launched on December 12, 2025, at Panagal Park Station in the presence of senior officials, general consultants, and representatives from the executing agencies. CMRL press release

Chennai Metro Phase 2 tunnelling and Corridor 4 scope

Phase 2 spans a total length of 118.9 km with 128 stations across three corridors. Railway Supply has also described the broader Phase 2 programme and its construction milestones. Within that programme, Corridor 4 runs from Light House to Poonamallee Bypass over 26.1 km, including a long underground section between Light House at Marina Beach and the Kodambakkam Flyover.

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The underground civil works on Corridor 4 have been split into two packages—UG-01 and UG-02—each covering about 4 km of twin tunnels. In total, the corridor’s underground tunnelling is around 16 km when both directions are counted. CMRL has deployed four TBMs on the project, each with an excavated diameter of 6.67 metres.

What TBM Peacock has already delivered?

TBM Peacock is not new to Corridor 4. Earlier, it completed a roughly 2 km drive between Panagal Park and the Kodambakkam Ramp Retrieval Shaft, securing the first breakthrough on Corridor 4 on July 23, 2025. That stretch was completed beneath live Indian Railways tracks, demonstrating high engineering precision and safety standards.

After the breakthrough, the TBM was dismantled, taken back to Panagal Park, and assembled again for the next stage of work.

The 1,898-metre drive toward Boat Club and the key challenges

For this second drive, TBM Peacock will construct one of the twin tunnels over 1,898 metres toward Boat Club Station. The route brings a few technical hurdles: the TBM must pass beneath existing operational Phase 1 Metro tunnels near Nandanam Station, and the alignment reaches depths of up to 30.2 metres (100 feet) below ground level. The work is also being carried out under dense city infrastructure, where surface disruption needs to be kept to a minimum.

CMRL says the TBM has been launched on the Down Line of Corridor 4 and will advance from Panagal Park through Nandanam before being recovered at the retrieval shaft at Boat Club Station. As reported by Rail Analysis, the machine’s earlier drive from Panagal Park to Kodambakkam Ramp led to the July 23, 2025 breakthrough.

CMRL has set a target for completing this tunnel drive by November 2026. Once finished, the new section is expected to strengthen Chennai Metro Phase 2 and further support Chennai’s future-ready transit network and the city’s push toward faster and more sustainable transport.

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