When it opens in a few years, the Thirumayilai Metro Rail station will be an engineering marvel. It will be located at 35 metres below the ground with three platform levels, according to Chennai Metro Rail officials.
The officials say Thirumayilai will be one of the most challenging stations to build because of a host of problems, ranging from geological conditions to reduced road width.
Here, the station will have four levels — a large concourse and three platforms. Thirumayilai is one of the important interchange stations in Phase-II and two stretches meet at this station — Madhavaram to SIPCOT and Poonamallee to Light House.
In Phase-I and Phase-I extension, the upper track and the lower track are built at the same level in the platform. In Phase 2 at Thirumayilai, owing to lack adequate land and road width, there is a need to build three levels of platforms, officials say.
The trains operating between Madhavaram and SIPCOT will run at the first level (17 metres below the ground) and at the third level (35 metres below the ground), and at the second level (24 metres below the ground), trains on the Poonamallee-Light House stretch will be operated, they say.
“After soil investigations, we have found that at Thirumayilai, there are rocks and rocky soil. This will be very difficult for carrying out excavation for the construction of the station box or the diaphragm wall and also the tunnelling work,” an official said.
At present, as part of Phase-II, being implemented at a cost of ₹61,843 crore, Chennai Metro Rail has been executing the construction of diaphragm walls at various locations between Madhavaram and Taramani and in other areas for building underground stations.
Since this process is going to take 6-8 months to be completed, Chennai Metro Rail has been gearing up to start tunnelling late this year. The specifications for the tunnel-boring machines will be submitted by the contractors to Chennai Metro Rail. Once approved, the machines will go through factory assurance tests before reaching the city. Totally, 23 machines will be deployed for Phase-II in the coming months, officials say.
