In a major infrastructure milestone, India is set to build its first underwater road-cum-rail tunnel across the Brahmaputra river in Assam, significantly strengthening strategic as well as civilian connectivity in the Northeast.

An inter-ministerial panel chaired by the Expenditure Secretary has granted in-principle approval for the construction of a 15.8-km-long twin-tube underwater tunnel between Gohpur and Numaligarh. One of the two tubes will house a single railway track, making it the country’s first underwater tunnel designed for both road and rail transport.

Officials said the project has been conceived to ensure faster mobilisation of security forces and military equipment during emergencies, while also improving connectivity to Arunachal Pradesh, Manipur and other northeastern states. Once operational, the tunnel is expected to reduce travel time between Gohpur and Numaligarh from nearly six-and-a-half hours to just about 30 minutes. The effective travel distance will also come down sharply from around 240 km to 34 km.

The overall project length, including the underwater tunnel, approach roads and railway infrastructure, will be 33.7 km. The estimated project cost stands at approximately Rs 18,600 crore. The twin tunnels will be unidirectional, with two lanes each, and will be constructed at a depth of nearly 32 metres below the deepest bed level of the Brahmaputra.

As per the proposed design, the tube carrying the railway line will not permit vehicular movement during train operations. Trains will run on electricity on a specially designed ballastless track.

The cost of the project will be shared by the Ministry of Road Transport and Highways, the Ministry of Railways and the Ministry of Defence. Officials said the proposal will now be placed before the Union Cabinet for final approval, which is expected ahead of the upcoming Assam Assembly elections. The project is targeted for completion within five years of the award of work.

The inclusion of a railway track, officials noted, has increased the project cost but will substantially enhance long-term connectivity and strategic capability in the region.

News source: Rediff