India’s first underwater twin tube tunnel, capable of carrying both road vehicles and trains, has reportedly secured in-principle nod from the central government.
As per a report by The Times of India, an inter-ministerial panel, led by the expenditure secretary, has approved the 15.8km twin-tube project.
The tunnel will be built beneath the Brahmaputra river in the state of Assam.
It will link Gohpur on the north bank of the river with Numaligarh on the south.
The overall project length, including approach roads and rail track, will be 33.7km.
The entire project is estimated to cost about Rs186bn ($2.06bn).
According to the report, one of the two tubes will be designed to accommodate a single railway line.
This tunnel will feature a ballistic track, with trains operating on electric traction. When trains are in operation, road vehicles will not be permitted in that tube.
The twin tunnels are planned as two unidirectional carriageways, each with two lanes, to be constructed around 32m below the deepest point of the Brahmaputra’s riverbed.
The construction timeline is projected at five years from the date the contract is awarded.
Once operational, the link is expected to sharply cut the distance between Gohpur and Numaligarh from around 240km to 34km and bring down travel time from about six-and-a-half hours to roughly 30 minutes.
The corridor is anticipated to improve connectivity to Arunachal Pradesh, Manipur and other north-eastern states.
Funding for the project will be shared between the Ministry of Road Transport and Highways, Indian Railways and the Ministry of Defence, officials cited in the report said.
The proposal is to be placed before the Union Cabinet for formal approval, which, according to officials, could come before the next Assam assembly elections.
The finance ministry had earlier cleared a stand-alone road tunnel project estimated at around Rs149bn, with an 80:20 funding split between the road transport and defence ministries.
Subsequently, the government opted to pursue combined road-and-rail tunnels where viable, identifying three such locations: the so-called “chicken neck” corridor in the North-East, the Brahmaputra crossing in Assam, and the Maranahally–Addahole (Shiradi Ghat) section in Karnataka.
The Times of India had first reported this plan on 6 October 2025.
Officials cited in the latest report said the inclusion of a railway alignment in one of the tubes has increased the overall cost of the Brahmaputra tunnel scheme compared to the earlier road-only proposal.
