Overview
- Railway officials detailed a roughly 40 km plan between Tin Mile Haat and Rangapani with tracks laid about 20–24 metres below ground.
- One of the underground lines is planned to connect toward Bagdogra, which officials describe as strategically important for air defence.
- The surface double-line section is slated to be expanded to four tracks, and together with two underground lines would yield six parallel routes.
- Some reports cite a proposed 22 km underground tunnel segment within the alignment, though the final tunnel length has not been confirmed.
- The initiative is in detailed planning without announced construction start dates, budgets or clearances, and has drawn strong public backing from Assam Chief Minister Himanta Biswa Sarma.