Chennai’s Thirumayilai set for major connectivity boost with stacked Metro tunnels for smoother travel

Thirumayilai is going to be one of the most intricately designed underground metro stations in Chennai, as it will be approximately 39 metres below street level and have four levels below ground including a concourse, which means that it has more levels than any other metro station on the network.

In order to prevent acquiring land in the heavily congested areas of Kutchery Road, CMRL has decided to build vertical tunnels. This will allow trains to travel one on top of the other under the surface of the area, which allows metro trains to run through densely populated areas without having to disrupt any of the existing buildings.

Thirumayilai will be the intersection point of Corridor 4(Lighthouse-Poonamallee) and Corridor 3(Madhavaram-SIPCOT). Both corridors will be crossing underneath each other, with the two tunnels crossing at different elevations before they diverge from each other past the Thirumayilai station.

As trains approach and leave Thirumayilai station on the surface level, they will also drop down below and ascend back to the surface at different elevations. Although the distance travelled on the train track is very convoluted, commuters will be able to enjoy the ride smoothly with no signs of the underlying tunnel changes below them.

Due to the lack of available space along the routes of Royapettah High Road and Kutchery Road, CMRL has had to make an alternative route due to limited availability. The removal of the Foreshore Estate Station created a greater need to stop at Thirumayilai, which caused CMRL to plan for the Thirumayilai stop.

Stacked tunnels were chosen to make corridor changes simpler for passengers. Running Corridor 3 above and below Corridor 4 allows shorter walking distances within the station, reducing the effort needed to switch lines.

Multiple tunnel boring machines are working simultaneously toward Thirumayilai. TBMs Thamirabarani, Vaigai, Eagle and Flamingo are tunnelling from RK Salai, Mandaveli and Lighthouse, helping speed up construction on this critical stretch.

This section of Phase II, including Thirumayilai station, is slated for completion and inauguration in 2028. Once opened, it will serve as a major interchange, improving connectivity across large parts of Chennai.