Kolkata: Tunnelling below the river was an easy job compared to the challenge that lay ahead for the East-West Metro, said K Subrahmanian, vice-chairman and managing director of Afcons, the agency entrusted with the job of under-river tunnelling. The tunnel boring machine ( TBM ) will now pass below the most congested part of the city, dotted with heritage structures, unsafe buildings and the most populous workplaces. "Tunnelling below the Hooghly may sound crazy to a commoner. Moreover, there are three nationally protected monuments and a number of state-listed heritage structures," said an Afcons official.The entire journey of the TBM will be measured round the clock. The earth pressure, precise steering of the TBM, negotiating sharp curves — there are several engineering challenges ahead.

Source: Times of India July 03, 2017 00:22 UTC