KOLKATA: Over 100 years after an underwater railway line was proposed between Kolkata and Howrah by a British engineer born in India, trains are set to roll by tunnels underneath the Hooghly river after PM Narendra Modi throws open Kolkata Metro’s Green Line, aside from two others, on Wednesday.
The 4.8km Howrah Maidan-Esplanade stretch of the Green Line that the PM will inaugurate will probably be India’s first under-river transportation tunnel.

The title of Sir Harley Dalrymple-Hay will not be broadly recognized, however the Birbhum-born engineer, who had dreamt of an underwater railway in Kolkata way back to 1921, will determine in a presentation on the underwater Metro tunnel made earlier than the PM.

“The under-river tunnel is 13 metres beneath the riverbed and 37 metres (more than 120ft) below the ground surface. There was a chance of running into things like lost anchors or ship wreckage. To avoid surprises, we did four boreholes in the river to study the soil. Fortunately, there were no surprises,” mentioned S Paramasivan, MD of Afcons, the agency that has constructed the under-river part of the Metro line.
The Green Line operates a 9.2km service between Sector V in east Kolkata and Sealdah railway station.
Kolkata Metro Rail Corporation is implementing Rs 10,000-crore venture.