Chennai's urban transit landscape is poised for a significant transformation with the construction of one of its most ambitious underground metro stations at Thirumayilai. This engineering marvel, being built approximately 39 metres below street level, is set to become a major interchange hub, drastically improving connectivity across the city upon its targeted completion in 2028.
An Engineering Feat Beneath Congested Streets
The design of the Thirumayilai station is a direct response to the spatial challenges posed by its location. With very narrow roads and heavily congested areas like Kutchery Road and Royapettah High Road, the Chennai Metro Rail Limited (CMRL) faced significant constraints. To avoid land acquisition and disruption to existing buildings, engineers devised an innovative solution: building vertical, stacked tunnels.
This approach allows trains from different corridors to travel one on top of the other underground. It enables the metro to pass through densely populated zones without disturbing the surface infrastructure. The station itself will have four levels below ground, including a concourse, making it the metro network's station with the most underground levels.
A Crucial Interchange for Two Major Corridors
Thirumayilai's strategic importance stems from its role as the intersection point for two key corridors of Chennai Metro's Phase II. It will connect Corridor 4 (Lighthouse-Poonamallee) and Corridor 3 (Madhavaram-SIPCOT). The tunnels for these two lines will cross underneath each other at different elevations near the station before diverging.
This stacked tunnel design was specifically chosen to simplify passenger interchange. By running one corridor above the other, walking distances within the station for line changes are significantly reduced, making commutes more efficient and less strenuous for daily travellers.
Accelerated Construction with Multiple TBMs
To meet the 2028 deadline, construction is progressing at a rapid pace. CMRL has deployed four Tunnel Boring Machines (TBMs) simultaneously towards the Thirumayilai site. Named Thamirabarani, Vaigai, Eagle, and Flamingo, these massive machines are boring through the earth from different launch points including RK Salai, Mandaveli, and Lighthouse.
This multi-pronged tunnelling effort is crucial for speeding up work on this complex stretch. The need for the Thirumayilai stop was amplified after the planning stage, particularly following the removal of the proposed Foreshore Estate Station from the plans.
A Smooth Ride Despite Complex Underpinnings
While the railway alignment is exceptionally convoluted—with trains descending, ascending, and crossing at different elevations as they approach and leave the station—commuters are promised a seamless experience. Passengers will feel no signs of the underlying tunnel changes during their journey, enjoying a smooth ride despite the intricate engineering below.
The entire section of Phase II that includes the Thirumayilai station is slated for inauguration in 2028. Once operational, it is expected to serve as a vital node, enhancing public transport access and reducing travel time for residents across large parts of Chennai, marking a new chapter in the city's infrastructure development.
