Atal Tunnel which reduces the travel time between Manali to Leh by four to five hours, was inaugurated by Prime Minister Narendra Modi on Saturday. The world’s longest highway tunnel by altitude will connect Manali to Lahaul-Spiti valley throughout the year. The valley was earlier cut off for about six months every year due to heavy snowfall. The decision to construct the tunnel was taken by Atal Bihari Vajpayee-led government back in June of 2000. It was previously referred to as Rohtang Tunnel. The Narendra Modi-led government later decided to name it Atal Tunnel in memory of the former Prime Minister Atal Bihari Vajpayee.
Take a look at world’s longest high-altitude tunnel
The 9.02-kilometre long tunnel is built with ultra-modern specifications in the Pir Panjal range of Himalayas at an altitude of 3,000 meters from the Mean Sea Level (MSL).
The south portal (SP) of Atal Tunnel is located at a distance of 25 km from Manali at an altitude of 3,060 metres, while the north portal (NP) of the tunnel is located near village Teling, Sissu, in Lahaul Valley at an altitude of 3,071 metres.
It is a horse shoe shaped, single-tube double lane tunnel with a roadway of 8 metres and has an overhead clearance of 5.525 metres, the PMO said. It has been designed for traffic density of 3000 cars per day and 1500 trucks per day with max speed of 80 km/hr.
It has the state of the art electromechanical system including semi transverse ventilation system, SCADA controlled firefighting, illumination and monitoring system.
The tunnel, built at a cost of about ₹3,300 crore, is extremely significant from the point of view of the country’s defence, the officials said. The most difficult stretch was the 587-metre Seri Nalah Fault Zone. The breakthrough from both ends was achieved on October 15, 2017.
The major part of the construction was done by Border Roads Organization (BRO). They had to overcome a number of weather, terrain and geological challenges to build the tunnel.
Talking about the tunnel, a BRO official said it provides a telephone facility at every 150 metre of its stretch, a fire hydrant every 60 metre, emergency exits every 500 metre, turning cavern every 2.2 kilometre, air quality monitors every 1 km, broadcasting system and automatic incident detection system with CCTV cameras every 250 metre.
