Underwater Metro Kolkata: PM Modi to inaugurate first of its kind rail line today; Details here

The PM will officially open the 4.8 km Howrah Maidan-Esplanade segment of the Green Line, which will be India's first subterranean transit tube. Trains are expected to travel through tunnels beneath the Hooghly river when PM Narendra Modi opens Kolkata Metro's Green connection on Wednesday, along with two other lines, more than a century after an underwater railway connection between Kolkata and Howrah was suggested by a British engineer born in India. 

As part of his 10-day tour to 12 states and union territories (UTs), Prime Minister Narendra Modi will launch and lay the foundation stone of several projects worth ₹15,400 crore in Kolkata on Wednesday, March 6. In five days, this will be his second trip to West Bengal.

Watch overview here:

Construction phase 

Afcons is the company that built the Metro line's under-river segment. The under-river tunnel is 37 meters (more than 120 feet) below the earth's surface and 13 meters below the riverbed, according to S Paramasivan, MD of Afcons. 

There was a possibility of encountering wreckage from ships or lost anchors. We dug four boreholes in the river to examine the soil to prevent surprises. Fortunately, nothing unexpected happened. Between the Sealdah railway station and Sector V in east Kolkata, there is a 9.2km service provided by the Green Line. Kolkata Metro Rail Corporation is working on a project of Rs 10,000 crore.

An official announcement states that the 4.8 kilometer East-West Metro route was constructed for ₹4,965 crore. Howrah will have the lowest Metro station in India, 30 meters below the surface. 

Project's engineer

The engineer from Birbhum, Sir Harley Dalrymple-Hay, may not be well-known, but he will be mentioned in a presentation on the underwater Metro tunnel given in front of the PM. Harley had first imagined an underwater railway in Kolkata as early as 1921.