India has achieved a significant milestone in railway infrastructure with the successful breakthrough of Tunnel No. 8 in the Rishikesh-Karnaprayag Railway Project, located in the challenging terrain of Uttarakhand. At 14.58 kilometre, this tunnel is set to become the longest transport tunnel in the country, surpassing existing tunnels in Jammu and Kashmir and Himachal Pradesh.

The breakthrough marks a major step in the development of the Rishikesh-Karnaprayag broad gauge railway line, which aims to enhance connectivity in Uttarakhand. The line will link important towns such as Devprayag, Srinagar, Rudraprayag, Gauchar, and Karnaprayag, spanning five districts: Dehradun, Tehri Garhwal, Pauri Garhwal, Rudraprayag, and Chamoli. The project is expected to promote tourism, support local businesses, and significantly reduce travel time across the region.

Constructing the tunnel through the Himalayan terrain has been an engineering feat, with the project involving a total of 213.57 kilometre of tunnels, including 16 main tunnels, 12 escape tunnels, and 7.05 kilometre of cross passages. As of now, 195 kilometre have been completed. Notably, the project marked the first successful use of a Tunnel Boring Machine (TBM) in the Himalayan region, with the TBM completing 10.4 kilometre of excavation. The rest of the tunnel work was carried out using the New Austrian Tunnelling Method (NATM).

Building the tunnel was a challenging task due to weak rock formations, heavy overburden, and water inflows of up to 2,000 litre per minute in some sections. Additionally, the project includes 19 major bridges, five important ones, and 38 minor bridges, with key structures over the Chandrabhaga and Alaknanda rivers already completed.

News source: India Today