Chennai Metro Rail completes tunnel linking Greenways Road with Mandaveli

Chennai Metro Rail has created yet another tunnel in corridor 3 of the phase II project and finally linked Greenways Road with Mandaveli on Saturday (October 18, 2025). Earlier, Chennai Metro Rail finished building a tunnel in corridor 3, which connects Royapettah with Dr. Radhakrishnan Salai.

In the 118.9 km phase II project with three corridors—Madhavaram to SIPCOT (corridor 3), Light House to Poonamallee (corridor 4) and Madhavaram to Sholinganallur (corridor 5), all of them are planned as a mix of elevated and underground networks. But corridor 3 has the maximum extent of underground network. The entire length of this corridor is 45.8 km and of this, 26.7 km travels underground. Corridor 3’s underground network commences at Madhavaram and passes through numerous dense, residential, commercial areas including Perambur, Ayanavaram, Purasawalkam, Kilpauk, Chetpet, Nungambakkam, Thousand Lights, Royapettah, Dr Radhakrishnan Salai, Greenways Road, Mandaveli, Adyar and Taramani. After Taramani, the corridor is built elevated along the IT corridor till SIPCOT.

The two tunnel boring machines (TBM) ‘Vaigai’ and ‘Noyyal’ began boring at Greenways Road nearly two years back; of that, the machine ‘Vaigai’ made a breakthrough at Mandaveli on Saturday (October 18, 2025).

According to officials of Chennai Metro Rail Limited (CMRL), the total length of the tunnel was 775 metres from Greenways Road to Mandaveli, and the machines drilled underneath 75 buildings and densely built-up areas. Be it sewer lines, water and electricity lines, or the presence of various utilities, it was very challenging to build the shaft at Mandaveli.

Sources said, the TBMs were waiting closer to the station for quite some time as there were delays in finishing the diaphragm wall of the Mandaveli station.

The machines bored through silty sand and sandy ground conditions. As far as the machine ‘Vaigai’ is concerned, the cutter head, a component of the TBM, was changed 13 times. In November, the next machine, ‘Noyyal,’ too, will reach Mandaveli.