Kolkata: Construction of the underground tunnel for the East-West Metro railway from Esplanade to Sealdah will start from next Thursday.It will take one year to one-and-a-half years to complete the construction on the most difficult terrain and work will go on, keeping the traffic flow intact. Senior officials of the Kolkata Municipal Corporation (KMC) said the construction of the tunnel will be very difficult as there are many buildings more than 100 years old on the route chosen. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThere are a couple of buildings more than a century old including the headquarters of the Kolkata Municipal Corporation, Metropolitan Building and the residence of Rani Rashmoni at Janbazar among others. The Kolkata Metro Rail Corporation Limited (KMRCL) had vacated the old buildings during the construction of an underground tunnel off Brabourne Road and a similar method will be followed here as well. The KMRCL will vacate old premises and rehabilitate the inhabitants. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseThe underground tunnel will be constructed below S N Banerjee Road up to the Bank of India branch and then Sealdah. The Tunnel Boring machine (TBM) will start digging from next Thursday. As there is heavy flow of traffic in areas around Esplanade special precautionary measures will be taken. Senior civic officials said the physical health of the old buildings has been examined and problems are not likely to occur. The total length of the East-West Metro line is 16.6 km. The elevated corridor is 5.8 km and underground is 10.8 km. An 11 km long tunnel has been constructed under river Hooghly. The construction of the East-West Metro in Salt Lake is complete and the coaches are being given a trial run.