Engineering marvel at 10,000 feet

Vijay Mohan 

We could see light at the end of the tunnel. The many thousand watt bulbs illuminate the dome, aiding the construction work round the clock. All this to ensure that the winter of next year is different, for the first time. For the first time, Rohtang Pass, at an altitude of 13,050 feet, will be navigable throughout the year. 

The pass got its name from its history of claiming lives of those who tried to cross it. In local jargon, Ro is corpse and thang means field. It came to be known as the field of corpses. It won’t be so anymore.  By the end of 2019, an 8.8 km tunnel will make it possible for people to travel between Lahaul-Spiti in the north and Kullu Valley in the south, cutting the journey by 46 km and saving over four hours.

Work on the construction site was started by the Border Roads Organisation in 2010. The earlier deadline for the completion of the project was 2015, but geological challenges and heavy ingress of water from an overhead stream stalled the work. Drilling a tunnel wide enough to accommodate two-way traffic speeding up to 80 kmph, along with an underground emergency escape channel and an overhead ventilation system, was a mammoth task. It called for best-of-world’s engineering skills. 

At an altitude of 10,000 feet, the tunnel’s maximum depth is 6,000 feet below the surface. The tunnel’s north portal lies at Sissu, which is 13 km from the base of Rohtang Pass, while the southern portal is near Solang, about 15 km from Manali.