The Chennai Metro Rail Limited (CMRL) conducted factory acceptance test for the first tunnel boring machine (TBM) in corridor 4 (from Lighthouse to Poonamallee bypass) in the underground portion 1 of the construction.

The Metro Rail is currently constructing the underground section in corridor 4 in two portions, UG 1 and UG 2, each of which contains four km of twin tunnels. It is planning to use four tunnel boring machines for the section measuring 16 km in both upline and downline tunnels.

As per a note from CMRL, ITD Cementation India Limited, the contractor, would use the machines manufactured by the German company, Herrenknecht. As part of the procedure, the first factory acceptance test of the first tunnel boring machine was held at the HK factory in Ponneri in the presence of CMRL project director T Archunan.

The TBM named S1073B has a bore diametre of 6.670 metres and 110-metre-long earth pressure balance. The massive machine, weighing 700 tonnes, will be dismantled to be transported and placed at the destination at Light House station.

The construction of a launching shaft to receive the TBM is currently under way at the Light House station, and is expected to be ready by May.

The TBM will be launched downline of corridor 4 and will mine at a maximum depth of 29 metre below ground starting from Light House, Kutchery Road, Tirumaylai, Alwarpet, Bharatidasan and lastly scheduled to arrive at Boat Club by May 2025.

The phase II of Metro Rail construction is currently undertaken for 118.9 km, with 128 stations in three corridors.