Twin Tubes, One Vision: India’s First Multi-Modal Underwater Tunnel.

India is set to construct its first twin-tube underwater tunnel beneath the Brahmaputra River in Assam, designed to carry both road traffic and trains, marking a major infrastructure boost for the Northeast.

An inter-ministerial committee chaired by the Expenditure Secretary has granted in-principle approval to the project, which will connect Gohpur and Numaligarh. The 15.8-km-long tunnel will form the core of a 33.7-km corridor that includes approach roads and a railway line.

One tunnel tube will accommodate a single electrified, ballastless railway track, with road traffic temporarily suspended during train movement. The second tube will be dedicated to road transport, featuring two unidirectional lanes for vehicles. Constructed approximately 32 metres below the riverbed, the tunnel is expected to significantly enhance both civilian connectivity and rapid military deployment.

Once operational, travel time between the two points is projected to reduce from more than six hours to about 30 minutes, while the distance will shrink from 240 km to 34 km. Estimated to cost ₹18,600 crore, the project is likely to be completed within five years following Cabinet approval, ahead of the Assam Assembly elections.

News by Rahul Yelligetti.