Chennai Metro breakthrough: Tunnelling between Lighthouse and Thirumayilai stations completed, boosting connectivity to Marina Beach

Getting to Marina Beach from Poonamallee may soon be easier, as Chennai Metro Rail Limited (CMRL) completed the tunnelling work between Lighthouse and Thirumayilai metro stations on Friday.

In an official release, CMRL stated that the tunnel boring machine (TBM) Flamingo successfully finished the downline tunnel and achieved breakthrough on Friday.

The upline tunnel between Lighthouse and Thirumayilai stations had been completed earlier by TBM Eagle on February 9, forming part of the ongoing construction of Corridor-4 (Lighthouse–Poonamallee Bypass).​

The section is part of the 26.1-km Corridor-4, which will connect Lighthouse to Poonamallee Bypass, significantly improving connectivity across Chennai once fully operational.

The tunnel, measuring 1,985 metres in length, was constructed by Cemindia Projects Limited and passes beneath some of the city’s most sensitive and congested zones.

The tunnel runs under critical locations including the Lighthouse area, All India Radio campus, Russian Embassy zone, Rosary Church, the MRTS bridge, and Buckingham Canal, highlighting the complexity of the project.

CMRL noted that the tunnelling faced challenging geological conditions such as rocky strata, shallow and deep overburden due to stacked tunnel configuration, and unforeseen gas pockets, all successfully navigated by the TBMs.