India’s First Underwater Rail Tunnel Under The Hooghly River Completed Before Deadline

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2:28 pm 29 May, 2017

India’s first underwater rail tunnel connecting Howrah to Salt Lake, Kolkata, is complete well ahead of schedule, its deadline being July, 2017.

The 502 meter-long tunnel under the Hooghly River is dug jointly by Afcons Transtonnelstroy and Kolkata Metro Railway Corporation Ltd.

India Today reports that the underwater tunnel was constructed by making use of Rachna, a massive tunnel-boring machine (TBM), which was brought from Herrenknecht AG plant in Schwanau, Germany.


Of the entire 16.6 km East West Metro of Kolkata connecting the twin cities of Howrah and Kolkata, 10.8 km is constructed underground, of which 502 meters is under water. Digging this underwater tunnel was the most critical part of the metro line construction.

The entire stretch will have a total of 12 stations, of which 6 will be underground.

The project faced several delays since it started, owing to issues related to slum relocation, land allocation and route alignment. But now, the completion of the boring of this tunnel ahead of deadline comes as wonderful news.

The final commissioning of the metro line is expected by the end of 2019 and the route will be operational after that.