Cabinet Approves Rs 18,662 Crore Brahmaputra Underwater Road Tunnel Project

In a landmark infrastructure decision with far-reaching implications for the Northeast, the Cabinet Committee on Economic Affairs, chaired by Prime Minister Narendra Modi, has approved the construction of a twin-tube underwater road tunnel beneath the Brahmaputra River in Assam, integrating rail infrastructure within one of the tubes.

The ambitious 33.7-kilometre greenfield project will connect Gohpur on NH-15 with Numaligarh on NH-715 and will include a 15.79-kilometre road-cum-rail tunnel under the Brahmaputra. The total capital outlay for the project stands at ₹18,662.02 crore. It will be executed under the Engineering Procurement Construction (EPC) mode. Once completed, the tunnel will become India’s first underwater road-cum-rail tunnel and only the second such project globally.

 A Strategic Connectivity Leap

At present, road connectivity between Gohpur and Numaligarh involves a circuitous 240-kilometre stretch via the Kaliabhomora bridge near Silghat, passing through Kaziranga and Biswanath. The journey takes nearly six hours and is prone to congestion, especially along ecologically sensitive zones.

The new access-controlled four-lane corridor is expected to drastically reduce travel time while offering a direct, safer and more efficient alternative. It will also ease pressure on routes cutting through Kaziranga National Park, a UNESCO World Heritage Site frequently affected by heavy traffic and seasonal flooding.

Officials say the project will significantly enhance freight efficiency, lower logistics costs, and strengthen economic integration across Assam, Arunachal Pradesh, Nagaland and other Northeastern states.

 Engineering and Design Highlights

The project will feature a Twin Tube Tunnel Boring Machine (TBM) system, with two lanes in each tube. One of the tubes will also accommodate railway infrastructure, integrating seamlessly with existing rail networks.

The tunnel alignment will connect with two major national highways, NH-15 and NH-715, and link two railway sections under the Northeast Frontier Railway (NFR):

• Rangia–Mukongselek section under Rangia Division (Gohpur side)
• Furkating–Mariani loop line under Tinsukia Division (Numaligarh side)

In addition to the 15.79-km underwater tunnel, the project includes 1.26 km of road cut-and-cover and 4 km of rail cut-and-cover sections.

 Multi-Modal Integration Across the Region

The corridor is designed to serve as a multi-modal integration hub. It will connect:

• 2 Airports: Donyi Polo (Holongi) Airport, Itanagar and Tezpur Airport
• 4 Major Railway Stations: Numaligarh, Gohpur, Golaghat Town and Simaluguri Junction
• 2 Inland Waterway Terminals: Biswanath Ghat and Tezpur

The alignment will also link 11 economic nodes, including Numaligarh Industrial Area, IIDC Titabor, IIDC Demow and MMLP Jogighopa, among others. Three key social nodes, including tribal district Dima Hasao and aspirational districts Udalguri and Darrang, will benefit from improved accessibility. Tourism is also expected to gain momentum, with improved connectivity to Kaziranga National Park and Deopahar Archaeological Site.

 Economic and Strategic Implications

Beyond easing civilian movement, the tunnel is being seen as strategically vital given the Northeast’s proximity to international borders. Faster troop and equipment mobility, especially towards Arunachal Pradesh, will strengthen logistical preparedness.

The government estimates that the project will generate nearly 80 lakh person-days of direct and indirect employment during construction, offering a substantial boost to the local economy.

The Annual Average Daily Traffic (AADT) projected for FY-25 stands at 4,680 Passenger Car Units (PCU), a figure expected to rise steadily once the corridor becomes operational.

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