Chennai Metro Update: First Tunnel Boring Machine 'Kurinji' Launched At Kolathur Ramp

After the successful completion of the Phase I and Phase I Extension Corridors, Chennai Metro Rail Limited (CMRL) has commenced the expansion of the city's metro rail network under Phase II on Thursday.

With ridership on Corridors 1 and 2 steadily growing since their launch in June 2015, CMRL is now embarking on an ambitious infrastructure project that will add three new corridors spanning a total of 118.9 km. The project is being funded by multiple international agencies, including the Japan International Cooperation Agency (JICA), Asian Development Bank (ADB), Asian Infrastructure Investment Bank (AIIB), and New Development Bank (NDB).

Corridor 5: A Game-Changer for Chennai's Connectivity

One of the key components of Phase II is Corridor 5, which will stretch 47.0 km from Madhavaram Milk Colony to Shollinganallur. This corridor will pass through major hubs like Koyambedu, Porur, and Alandur, connecting residential and commercial areas across the city. The corridor will feature 5 underground stations and 39 elevated stations, significantly enhancing Chennai's public transportation network.

Tunnel Boring Machines (TBMs) Named After Tamil Landscapes

The construction of Corridor 5's underground section involves the deployment of four Tunnel Boring Machines (TBMs), each named after distinct Tamil landscapes: Kurinji, Mullai, Marutham, and Neithal. The first TBM, Kurinji, was launched today (February 19, 2025) and will bore a 246-meter tunnel from Kolathur Ramp towards Kolathur Station (upline). It is expected to complete this segment by June 2025. After retrieval, Kurinji will be relaunched from the south shaft to tunnel towards Srinivasa Nagar, covering an additional 1.06 km.

The second TBM, Mullai, is scheduled to arrive by the end of March 2025 and will begin tunnelling near Villivakkam Railway Station towards Villivakkam Bus Terminus, covering 603 meters. The remaining two TBMs, Marutham and Neithal, will be launched based on site readiness.

7.8 km Underground Tunnel Section Underway

The underground section of Corridor 5 spans 7.8 km, with twin tunnels of 3.9 km each. This section includes five underground stations from Kolathur Ramp to Nathamuni Ramp. The construction is being executed by M/s. Tata Projects Limited, which has mobilized all four TBMs for the project.