The project is aimed at enabling faster movement of security forces and military equipment during exigencies, while also improving connectivity to Arunachal Pradesh, Manipur and other north eastern states.
In a first of its kind, India is set to build a twin-tube underwater tunnel across the Brahmaputra in Assam, with provision for both vehicular traffic and train movement, significantly enhancing strategic and civilian connectivity in the north east.
An inter-ministerial panel headed by the expenditure secretary has given in-principle approval for construction of a 15.8 km-long twin-tube tunnel connecting Gohpur and Numaligarh.
One of the tubes will include a single railway track, making it India's first underwater road-cum-rail tunnel.
Officials said the project is aimed at enabling faster movement of security forces and military equipment during exigencies, while also improving connectivity to Arunachal Pradesh, Manipur and other northeastern states.
Once completed, the tunnel will reduce travel time between Gohpur and Numaligarh from the current six-and-a-half hours to just 30 minutes. The distance will shrink dramatically from about 240 km to 34 km.
The overall project length will be 33.7 km, including the underwater tunnel, approach roads and railway track, at an estimated cost of around Rs 18,600 crore (Rs 186 billion).
The twin tunnels will be unidirectional, with two lanes each, and constructed at a depth of about 32 metres below the deepest bed level of the Brahmaputra.
As per the design, the tube carrying the railway track will not allow vehicular movement when trains are operating. Trains will run on electricity on a specially designed ballastless track.
The project cost will be shared by the ministry of road transport and highways, ministry of railways and the ministry of defence.
Officials said the proposal will now be placed before the Union Cabinet for final approval, which could come ahead of the upcoming Assam assembly elections. The project is expected to be completed within five years after the award of work.
Last year, the finance ministry had cleared a Rs 14,900 crore (Rs 149 billion) road-only tunnel across the Brahmaputra with an 80:20 funding pattern between the road transport and defence ministries.
However, following a policy decision to construct road-cum-rail tunnels wherever feasible, the government identified three such projects -- one across the Brahmaputra in Assam, another in the north east's 'chicken neck' corridor, and a third on the Maranahally-Addahole (Shiradi Ghat) stretch in Karnataka.
Officials said the inclusion of a railway track in one of the tunnels has led to the increase in project cost, but will significantly enhance long-term connectivity and strategic capability in the region.
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