The low-cost New Austrian Tunnelling Method will be used in Vizhinjam to construct the third-largest railway tunnel in the country. It is the first subterranean road in the nation built with low-cost, contemporary drilling and blasting technology rather than the costly tunnel boring machine approach. It doesn't require a lot of room either. It only takes 5.5 hectares of land instead of the originally needed 65 hectares because it is an underground road. In order to reinforce the sides, New Austrian Tunnelling employs drilling that involves breaking and grinding the rock in accordance with its structure and nature.

The detailed project report (DPR) for the subterranean railway that will be built for container movement at Vizhinjam port was authorised by the project construction committee, which was presided over by Chief Secretary Dr. V Venu. Construction is the responsibility of Konkan Railway. The port to main railway line at Balaramapuram is connected by a 10.76-kilometer route. 9.5 kilometres of this are underground. It is anticipated that the subterranean road would be finished in 42 months. The tunnel will take three years to build. The port is now nearing completion.

The first phase will be inaugurated in September. A trial run will be held next month after bringing containers on two huge barges.The other two largest railway tunnels in the country are the 12.75 km tunnel, part of the Udhampur-Srinagar-Baramulla rail link and the 11.2 km long Pir Panjal. Container removal will be by road until the construction of the railway is completed. For this, the port road was widened by connecting it with the Kanyakumari highway. The construction will be done jointly by the port company and the state government. Central assistance will also be sought to find the money.