Kolkata, India (Metro Rail Today): The construction of the country’s first underwater metro tunnel under the Hooghly river in Kolkata is underway and it is likely to become fully functional by the end of the year 2023. This underwater metro tunnel will connect metro services between Howrah and Kolkata.
The 520 meters long underwater tunnel is part of the 16.6km East-West Metro Corridor of the Kolkata Metro Rail Project and it is being built under the river bed. The total length of the tunnel is 10.8 km in both directions (up & down line). This tunnel is being developed 33 meters below the riverbed by the consortium of Afcons Infrastructure Limited and Transtonnelstroy Limited.
This tunnel will connect Howrah Maidan Metro Station and Esplanade Metro Station. Two tunnel boring machines (nicknamed Rachna & Prerana) brought from Herrenknecht are being used to dig the tunnel. Tunnelling work was started from Howrah Maidan and one of the TBM 'Rachna' had completed the tunneling under the Hooghly River in 36 days on 23rd May 2017. The other TBM 'Prerna' also completed the tunneling work under the river on 21 June 2017.
According to Mithun Ghosh, the site supervisor, there will be walkways in the tunnels for the evacuation of passengers in case of emergency. Besides, important passagework has been done as well, considering that if a technical problem arises inside the water tunnel area, commuters can be taken out of the tunnel through the special passage. Ghosh further said that nearly 80 percent of the development work of the East-west Howrah Metro station is already completed and the full-fledged service is expected to start in the year 2023.
"The metro station is being constructed under the Hooghly river at a depth of 33 meters. So far, 80 percent of the construction work has been completed while 20 percent of work is yet to be finished. By 2023, it will start functioning," said Mithun Ghosh.
The East-West Metro Corridor (Line 2) is being implemented by Kolkata Metro Rail Corporation Limited.