Metro Rail tunnelling work has reached the next stop on one portion of the Airport-Washermenpet stretch.

Two tunnel-boring machines (TBMs) have drilled their way to Government Estate on Anna Salai from May Day park in Chintadripet.

Each of the TBMs has tunnelled a distance of 417 metres to arrive at the Government Estate station, said an official of Chennai Metro Rail Limited (CMRL).

“The two TBMs have broken the diaphragm wall — a box-like structure of about one-metre thickness built around the four sides of the station — at Government Estate and will now be taken to the other end of the station from where the machines will drill towards LIC, the next stop,” the official said.

The two TBMs were brought from Russia and about five Russians are engaged in the underground work with several other workers. The TBMs were launched on this stretch way back in November 2012 and the tunnelling began subsequently. Soon after it was commissioned, one of the machines developed a technical problem and this had caused some delay in the work.

CMRL has deployed 11 TBMs at various work sites across the city. The TBMs have the capacity to drill at a speed of about 6-8 metres a day which can be increased or decreased depending on soil conditions. Simultaneously, two other TBMs are tunnelling from Saidapet station to AG-DMS station on the Airport-Washermenpet stretch.