Rail Vikas Nigam Limited (RVNL) has achieved a significant milestone by completing the breakthrough of India’s longest railway tunnel, which stretches 14.6 km between Devprayag and Janasu in Uttarakhand.
This accomplishment marks a major step forward in the ambitious 125 km Rishikesh-Karnaprayag rail project, designed to improve regional connectivity by linking important towns such as Devprayag, Srinagar, Rudraprayag, Gauchar, and Karnaprayag.
Upon its completion, the rail line is anticipated to greatly reduce travel times, offer all-weather access to remote regions, and stimulate tourism and economic growth throughout Uttarakhand.
During a site visit, Railway Minister Ashwini Vaishnaw emphasized the challenges presented by the young Himalayan landscape, stating, “This is a twin tunnel project, and the conventional tunnel boring machine (TBM) method was inadequate for the Himalayan region. However, we were determined and consulted with some of the world’s leading engineers.” Ultimately, the Himalayan Tunnelling Method (HTM) was employed, a technique previously utilized in the construction of the Katra-Banihal section of the Kashmir rail link project. This method incorporates pre-excavation support measures to address the ‘flowing conditions’ encountered during the tunneling process.
The project required the transportation of 165 MT of TBM components from Mundra port to the construction site, navigating narrow Himalayan roads and aging bridges. The tunnel is situated in Seismic Zone IV, an area prone to tectonic activity, necessitating advanced design features and ongoing geological assessments. RVNL has managed the project from its initial concept through to commissioning, with final touches expected to be completed shortly.
