CHENNAI: It was a historic moment for Metro Rail when a giant tunnel boring machine brought down the concrete
slab between the ramp linking Koyambedu with Thirumangalam.
The 5km-stretch tunnel was well lit exhibiting the tireless efforts of the unsung metro rail workers, engaged in this task for nearly two years.
“The entire tunnel work comprises five packages and this is the fifth and the first one to be completed,” said V K Singh, chief general manager of Chennai Metro Rail (CMR) (Underground Construction). “Work on this package started in December 2012. We have drilled 15 metre to 18 metre tunnel despite uneven surface. It was either clay or rocky, but the work went on smoothly,” he said.
Director of projects, CMR, R Ramanathan, said after this follows a phase of transition to link the tunnel to a box and from there to the ramp with an elevation of 60 metres before reaching Koyambedu station. The tunnels are designed with a walking space with cross passage at every 250 metres. The biggest challenge was shipping out the mud. It was transported through a chamber to a small train taking it to Shenoy Nagar, from where it was taken out by trucks and dumped at Tiruneermalai.
Over 70 per cent work of stations in the stretch - Shenoy Nagar, Anna Nagar East, Anna Nagar Tower and Thirumangalam - has been completed. Work on the Thirumangalam station concourse was progressing. The station has two fire exits besides two access points for firemen. Built 16 metre below the surface, passengers have to travel further eight metres below to catch the train. CMR would be the only one of its kind to have the underground stretch platform covered with doors. “They would open once the train arrives. Delhi metro has this facility only at the airport stretch,” he said.