Himalayan Feat

The construction of Rohtang Tunnel begins on June 28. Once completed, it will provide an all-weather route to Lahaul-Spiti and Ladakh, besides reducing the distance by 48 km, and saving travel time by nearly four hours, writes Vijay Mohan

Rohtang Pass is open to vehicular traffic only during summers

It has taken 27 years from the inception of the idea to laying the first stone. Conceived as far back as 1983 by former Prime Minister Rajiv Gandhi, construction of the much-hyped Rohtang tunnel in Himachal Pradesh is finally scheduled to commence on June 28 when UPA chairperson Sonia Gandhi lays it foundation.

The tunnel construction project received an impetus after the Kargil conflict. It will provide an all-weather alternate route to Ladakh through Himachal Pradesh via Manali and, of course, the famous Rohtang Pass, after which it takes its name. At present, the main route to this region is NH 1-A that reaches Jammu Kashmir from Punjab and passes through Srinagar, Sonmarg and Kargil up to Leh.

Located at an altitude of more than 13,000 feet in the Pir Panjal range, 51 km from Manali, Rohtang Pass remains snowbound in winters for nearly six months, cutting off the tribal Lahaul-Spiti Valley in Himachal as well as the strategically vital Ladakh region of Jammu and Kashmir.

The terrain and climate of the area pose serious problems in maintaining road communication for more than four months at a stretch. The area faces heavy snowfall, high-velocity winds and sub-zero temperatures.

Rohtang Tunnel will check the vagaries of nature that deny movement of men and machines during most part of the year. It is the most challenging task that the Border Roads Organisation (BRO) will undertake in its 50 years of existence. A laboratory of the Defence Research and Development Organisation (DRDO), the Snow and Research Studies Establishment (SASE), has been carrying out preliminary investigations and feasibility studies. The DRDO laboratory specialises in studies of snow physics, cold weather engineering and allied subjects.

BRO men at work on the approach road to the Rohtang Tunnel portal. Photos courtesy: Ministry of Defence

At 8.8 km and an elevation of about 10,000 feet, the Rohtang Tunnel would neither be the longest nor the highest in India or the world. Gotthard Base Railway Tunnel, nearing completion in the Alps Mountains of Switzerland, is 57 km long. Fenghuoshan Railway Tunnel, part of the Qinghai-Tibet Railway line in China, touches 16,000 feet.

What, then, makes Rohtang Tunnel unique as an engineering marvel is its main characteristic, which is a combination of both its length and altitude. According to the Ministry of Defence, when Rohtang Tunnel is completed in 2015, it would be the world’s longest tunnel at that altitude. In fact, it would be much longer than the longest tunnels anywhere around the world at altitudes over 7,500 feet.

The nearest in comparison to Rohtang Tunnel will be Anzob Road Tunnel in Tajikistan (5-km-long at 10,100 feet), Khojak Rail Tunnel, built by the British way back in 1891, near Quetta, in Pakistan (3.9 km at 11,700 feet) and Eisenhower Memorial Tunnel in the US (2.7 km, at 10,200 feet).

Interestingly, Rohtang Tunnel will not have the distinction of being the longest rail or road tunnel in India. This honour will go to the 11-km-long Pir Panjal Railway Tunnel at Banihal in Jammu and Kashmir, part of the Jammu-Srinagar railway line, which is due to be completed next year.

As of now, the longest tunnel in the country is the 6.5-km-long Karbude Tunnel in Ratnagiri district of Maharashtra, forming part of the Konkan Railway network.

Rohtang Tunnel was first conceived in 1983 so as to develop the Manali-Sarchu-Leh road as an all-weather alternate route for strategic considerations. A preliminary study was conducted in 1984 in consultation with the Geological Survey of India and the SASE.

The detailed feasibility study for the ambitious Rohtang Tunnel was approved at a meeting of the Border Roads Development Board on January 14, 1987, which was presided over by Rajiv Gandhi himself. It was planned that an access road leading to the actual tunnel site would be constructed first.

On May 26, 2002, former Prime Minister Atal Bihari Vajpayee laid foundation stone for the access road, costing Rs 180 crore. The access road to the south portal tunnel site, on which as many as 18 avalanche protection structures are being erected, was completed in 2005.

The Cabinet Committee on Security cleared the tunnel project in September 2009 at a cost of Rs 1,495 crore. Strabag-Afcons, a joint venture between India’s Afcons Infrastructure Ltd and Strabag SE of Austria, the world’s fourth largest construction company, was awarded the construction contract through a global tender.

At present, the preparatory work and induction of resources are under progress. The actual tunnelling work is expected to be completed by 2015. An international firm SMEC International has been engaged as consultants by the BRO for the Rohtang project.

The tunnel’s design, according to the Defence Ministry, will be novel in many ways. Due to its long distance and rarefied atmosphere at the heights it will be located, the tunnel will incorporate Semi-Transverse Ventilation System, where large fans would separately circulate air in and out throughout the length of the tunnel. The tunnel, with a horseshoe shaped cross-section, will be 11.25 m wide at road-level, providing ample room for two-way traffic and would cater to a maximum vehicular speed of 80 km/hr.

But the tunnel alone might not be enough to make the Manali-Keylong-Leh highway an all-weather road, as there are another two major snowbound passes along the way, Baralacha La and Tanglang La. To overcome this, the project envisages constructing a 292-km-long all-weather road, Nimu-Padam-Darcha, via Shinkun la, traversing the remote Zanskar region of J&K, estimated to cost an additional Rs 286 crore.

Once completed, Rohtang Tunnel will provide unhindered road access to the remote regions of Lahaul-Spiti and Ladakh throughout the year, besides reducing the distance by 48 km, and saving the travel time by nearly four hours. It will open up new vistas of trade and tourism and generate jobs for the local population.