Metro tunnels 42 meters in a month

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Chennaiites will not have to wait too long to have a sophisticated underground metro rail network crisscrossing the city.

A 42-meter long tunnel stands testimony to the city’s pride — part of what will be the first ever rail network running underground.

A month after launching the tunneling work from its Nehru Park site towards Egmore on July 28, Chennai Metro Rail Limited (CMRL) on Tuesday released the first ever pictures of the tunnel.

Senior CMRL officials said SUCG, a Chinese firm, and LT that is jointly executing the work at Nehru Park station site, has dredged 42 meters, or rather 35 rings (each ring measuring 1.2 meters in length) in a month.

The tunnel-boring machine (TBM) imported from China has a peak capacity of dredging 10 meters per day. The TBMs require human intervention as it dredges and builds the concrete ring or the layer of the tunnel automatically.

Till now, 11 TBMs have been imported from China for the 24 km of underground network of the total 45 km network bifurcated in to two corridors — Washermanpet to airport and Chennai Central to St Thomas Mount.

CMRL has set a 90-day deadline for completing the 939meter-long tunnel from Nehru Park to Egmore. “As the machine is new and dredging is only at the initial stages, the pace is relatively slow.

This would increase and the peak capacity would be achieved in the coming days,” said a senior CMRL official preferring anonymity.

The second TBM is expected to start tunneling from Nehru Park in the next 20 days. TBMs at Shenoy Nagar-Tirumangalam, May Day Park-Chennai Central and Washermanpet-High Court would start operating in September, officials said. The first TBM on Anna Salai would start boring in October.

Once the TBM completes tunneling till Egmore, it would be dismantled and reassembled for tunneling from the additional commissioner’s office (traffic) to Kilpauk by December.

By January 2013, all the 11 TBMs would be rolling across the city.