The 14.57-kilometer Tunnel T-8, part of the Rishikesh-Karnaprayag rail project, has achieved a breakthrough, marking a pivotal moment in the nation’s engineering endeavors.
Located between Devprayag and Janasu in Uttarakhand, Tunnel T-8 is set to become the country’s longest transportation tunnel, surpassing the 12.75 km Pir Panjal Railway Tunnel in Jammu and Kashmir. The breakthrough was achieved using a state-of-the-art Tunnel Boring Machine (TBM) named ‘Shakti,’ marking the first deployment of such technology for rail tunneling in India’s mountainous regions. The TBM achieved an average boring rate of 413 meters per month, positioning it among the fastest tunnel boring operations globally.
The Rishikesh-Karnaprayag rail project spans 125 kilometers and includes 17 tunnels and 35 bridges, with approximately 85% of the route running through tunnels. This strategic initiative aims to enhance connectivity in Uttarakhand, reduce travel time between Rishikesh and Karnaprayag from seven hours to two, and bolster economic activities in the region. The project, executed by Rail Vikas Nigam Limited (RVNL), faced numerous challenges due to the young Himalayan terrain, including complex and mixed rock types, high overburden pressure, and unstable mountain layers. To overcome these, engineers developed the Himalayan Tunneling Method (HTM), a modification of the conventional TBM approach, tailored to the region’s geological complexities
The successful breakthrough of Tunnel T-8 not only signifies a monumental engineering achievement but also underscores India’s commitment to enhancing its infrastructure in challenging terrains. The tunnel is expected to play a crucial role in facilitating the Char Dham Yatra and improving access to remote areas, thereby contributing to the region’s socio-economic development. As the finishing works progress, the completion of Tunnel T-8 stands as a testament to India’s growing expertise in executing large-scale infrastructure projects, even in the most demanding environments.
India Longest Rail Tunnel Nears Completion