India’s First Underwater Road-Rail Tunnel To Rise In Assam: ₹18,662 Crore Brahmaputra Mega Project To Slash Distance From 240 Km To 34 Km

Guwahati: Assam Chief Minister Himanta Biswa Sarma on Sunday described the proposed twin-tube underwater road-rail tunnel between Gohpur and Numaligarh as a game-changing project that will transform connectivity in the Northeast while strengthening national security.

The ambitious project, cleared by the Cabinet Committee on Economic Affairs, will be India’s first underwater road-cum-rail tunnel beneath the Brahmaputra and only the second such dual-use tunnel in the world after the Germany–Denmark link.

Addressing a press conference at Lok Sewa Bhawan, Sarma said the tunnel will shrink the present 240-km road distance between Gohpur and Numaligarh to just 34 km. Travel time, which currently takes nearly six hours, will be reduced to about 20 minutes.

“This will not only save time but change the way people and goods move across central and eastern Assam,” he said.

The project, estimated at Rs 18,662 crore, is expected to generate around 80 lakh human-days of employment during construction. Built nearly 57 metres below the Brahmaputra riverbed, the tunnel will have separate tubes for road and rail traffic, along with a dedicated escape passage. Cross-passages will be constructed every 500 metres to ensure safety in case of emergencies.

Sarma said the tunnel will improve links between Assam, Nagaland and Arunachal Pradesh, cutting travel distances and strengthening logistics. Flyovers and approach roads will be developed at both ends. While a flyover will connect the Gohpur side, multiple bridges are planned at Numaligarh, keeping in mind the sandy riverbed.

He said the project has four key stakeholders — the Indian Army, the Assam government, the Ministry of Road Transport and Highways through NHIDCL, and Indian Railways. The Ministry of Defence will bear around 20 per cent of the cost, given its strategic importance.

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Calling it more than a development project, Sarma said the tunnel will serve as a strategic lifeline. In situations where bridges or highways are disrupted, especially given the region’s narrow link to mainland India, the tunnel will ensure uninterrupted connectivity.

He added that the concept was shaped with inputs from former Chief of Defence Staff Bipin Rawat and National Security Adviser Ajit Doval.

Land acquisition will begin shortly, and the state aims to complete the project within five years. Once operational, the tunnel will become the fourth major Brahmaputra crossing with both road and rail facilities, marking a new chapter in the Northeast’s infrastructure story.