By rosebell
The latest breakthrough also marks the 10th tunnelling breakthrough on Corridor 3, highlighting continued progress on the underground sections of the Chennai Metro Phase II project.
Three Chennai Metro Phase II Tunnel Breakthroughs
The first breakthrough took place on September 29, when TBM Kaveri arrived at Kilpauk Medical College (KMC) Station on the down line of Corridor 3.
On September 30, TBM Maruthan completed its drive and reached Villivakkam Station on the down line of Corridor 5.
A third breakthrough followed on October 1, when TBM Adyar reached RK Salai Station on Corridor 3’s down line.
The three breakthroughs demonstrate progress across multiple underground construction packages and represent an important milestone for Chennai Metro Phase II tunnelling works.
Corridor 3 Tunnel Construction
Larsen & Toubro is constructing the 12km underground section of Corridor 3 between Kellys and Taramani.
On the section between Chetpet Station and KMC Station, TBMs Kaveri and Tamarabharani began tunnelling in February 2024. Tamarabharani completed the corresponding upline drive in November 2025.
The two TBMs had to excavate a 685m-long tunnel through challenging urban conditions. The alignment passed beneath five operational Southern Railway tracks near Chetpet Station, with approximately 18m of overburden.
Further along the route, tunnelling passed beneath the Chetpet Eco Park lake and several Kilpauk Medical College buildings, where overburden ranged from approximately 21m to 26m. The alignment also passed near existing Chennai Metro Phase I tunnels, with a minimum clearance of 6.1m.
TBM Adyar Completes 915m Drive
TBMs Bhavani and Adyar were launched in September 2024 to excavate the tunnel between Royapettah Station and RK Salai Station.
The upline TBM Bhavani completed its 910m drive in October 2025. TBM Adyar subsequently completed a 915m drive through silty sand, with overburden ranging from 9m to 13m.
Adyar’s breakthrough represents the 10th tunnelling breakthrough on the TU02 contract, adding another milestone to Corridor 3 construction.
TBM Maruthan Advances Corridor 5 Tunnelling
On Corridor 5, Tata Projects is responsible for an underground section with a total tunnel length of 7.88km.
Tata Projects launched TBM Maruthan on April 24, 2026, to excavate the 601m tunnel between Villivakkam Railway Station and Villivakkam Bus Terminus Metro Station.
The drive presented several tunnelling challenges, including excavation beneath five operational railway lines at Villivakkam Railway Station. Ground protection measures were also required because the alignment passes through a heavily populated residential area.
Chennai Metro Phase II Project
Chennai Metro Phase II comprises three metro corridors, extending the city’s rapid transit network by approximately 118.9km with 128 stations.
The project includes extensive underground construction using tunnel boring machines, with multiple contractors delivering different sections of the network.
Chennai Metro Phase II is scheduled for completion by the end of 2028. The latest sequence of breakthroughs on Corridors 3 and 5 marks further progress towards completing the city’s major metro expansion.
