India sets new tunnel construction record with Rishikesh-Karnaprayag rail line

L&T achieves a world-first in the Himalayan rail project, using advanced TBM technology to complete record-breaking tunnel excavation.

Larsen & Toubro (L&T) has achieved a new world record for tunnel building while working on the Rishikesh-Karnaprayag rail project in Uttarakhand. Using a single-shield hard rock tunnel boring machine (TBM) dubbed Shiv, the engineering giant excavated 790 meters in just 31 days, setting a new record in tunnel building. This astounding achievement was completed on June 29, 2025, along the 13.09-kilometre-long down-line tunnel connecting Devprayag and Janasu. This comes just months after its sister TBM Shakti made a breakthrough on the 14.57-kilometre up-line tunnel in April 2025, 12 days ahead of schedule.

This milestone is even more significant because it is the first time a single-shield hard rock TBM has been deployed in the Himalayan geology, which is brittle and intricate. The Devprayag-Janasu tunnel length is presently the world’s longest rail tunnel built with this type of machine. Both tunnels are approximately 30 kilometres long and incorporate auxiliary escape passages, cross-passages, and structural niches. L&T used a hybrid tunnelling method to complete this difficult terrain, with TBMs for 21 kilometres and the New Austrian Tunnelling Method (NATM) for the remaining 9 kilometres.

Executing a project in seismic zone IV presented major challenges. The TBM components, which weighed about 165 metric tonnes, had to be hauled down tight, winding Himalayan roads. The geology featured fractured rocks and high water infiltration zones, necessitating the creation of a novel tunnelling method. In response, L&T and Rail Vikas Nigam Limited (RVNL) created the “Himalayan Tunnelling Method”, a tailored approach that combines worldwide TBM technology with Indian engineering knowledge.

Once operational, the 125-kilometre Rishikesh-Karnaprayag train route is estimated to reduce travel time from seven hours to approximately two hours. Beyond boosting pilgrimage and tourism connectivity, the project is expected to create new economic prospects in Uttarakhand’s hill areas. The railway will improve regional mobility, increase local economies, and provide more reliable transport in disaster-prone areas.

Union Railway Minister Ashwini Vaishnaw and Uttarakhand Chief Minister Pushkar Singh Dhami attended the groundbreaking ceremonies and praised the project as a symbol of India’s growing engineering prowess. L&T’s leadership emphasised that the achievement was due to thorough planning, seamless coordination, and bold innovation. With the project set to be completed by December 2026, it represents a watershed moment in infrastructure development in one of India’s most difficult terrains.