Assam is set to get a major new road and rail link beneath the Brahmaputra River, aimed at improving connectivity between the northern and southern parts of the state. The project will combine road and rail infrastructure in a single underwater corridor and is expected to strengthen access to key destinations across the Northeast.
The project has now moved ahead with the invitation of bids for its construction, marking an important step towards implementation.
Rs 11,982 crore tender invited for project
As the project moves forward, the National Highways & Infrastructure Development Corporation Ltd (NHIDCL) has invited bids for the construction of the four-lane twin-tube road-cum-rail underwater tunnel under the Brahmaputra.
The tender, valued at Rs 11,982.36 crore, was issued on August 31, 2026. The last date for submitting bids is September 30, 2026.
The scope includes construction of the underwater tunnel, four-lane approach roads and railway infrastructure in one of the tubes. The project will be executed on the Engineering, Procurement and Construction (EPC) mode.
Brahmaputra underwater tunnel: Length, cost
The Brahmaputra underwater tunnel is part of the Gohpur-Numaligarh corridor in Assam, which will span around 33.7 km and connect Gohpur on NH-15 with Numaligarh on NH-715.
The underwater section will stretch 15.79 km and will have two tubes. Each tube will carry two road lanes, while one tube will also have railway infrastructure.
The underwater portion will be constructed using Tunnel Boring Machine (TBM) technology. The project will also include cut-and-cover sections and approach roads.
The total capital cost of the Gohpur-Numaligarh project is estimated at Rs 18,662 crore. The Union Cabinet approved the project in February 2026.
Gohpur-Numaligarh corridor: How it will improve connectivity
The new corridor will offer a shorter and more direct route between Gohpur and Numaligarh. At present, the road distance between the two places is around 240 km, with the journey taking nearly six hours.
The project is expected to cut travel time while making the movement of people and freight more efficient. It will also improve road connectivity to Arunachal Pradesh, Nagaland and other parts of the Northeast.
Road, rail and multimodal links
The project is planned to integrate with the existing road and railway networks on both sides of the Brahmaputra. On the Gohpur side, the corridor will connect with the Rangia-Mukongselek railway section. On the Numaligarh side, it will connect with the Furkating-Mariani loop line.
The corridor will also improve access to railway stations, airports and inland waterways, supporting movement across different modes of transport.
Access to Kaziranga and key centres
The corridor is also expected to improve access to several economic, logistics and tourism centres in Assam. These include Kaziranga National Park and the Deopahar Archaeological Site.
According to the government, the project will connect 11 economic nodes, eight logistics nodes and two tourist nodes. It will also provide connectivity to four major railway stations, two airports and two inland waterway terminals.