Atal Tunnel, An Engineering Marvel
ATAL TUNNEL, inaugurated by Prime Minister Narendra Modi on October 3, 2020 at Rohtang, is the world’s longest highway tunnel.
9.02-kilometre-long, the tunnel ensures all-weather connectivity between Manali and Lahaul-Spiti Valley.
The tunnel cuts the road distance between Manali and Leh by 46 kilometres and the travel time by about 4 to 5 hours. Earlier the Valley was cut off for about six months every year owing to heavy snowfall.
The South Portal of tunnel is located at a distance of 25-kilometre from Manali at an altitude of 3,060 metres, while its North Portal is located near village Teling, Sissu, in Lahaul Valley at an altitude of 3,071 metres.
It is a horseshoe-shaped, singletube double-lane tunnel with a roadway of 8-metre. It has an overhead clearance of 5.525 metres.
In 2005, the tunnel was estimated to cost about Rs 900 Crore. But persistent delays pushed the cost to Rs 3,200 Crore, which was more than three times the original cost estimated.
Key Safety features of the ATAL TUNNEL
- Entry barriers at both Portals
- Telephone at every 150-metre
- Fire hydrant mechanisms at every 60-metre
- Auto incident detection system with CCTV cameras
- Air quality monitoring at every kilometre
- Evacuation lighting/exit signs at every 25-metre
- Broadcasting system throughout the tunnel
- Fire-rated dampers at every 50-metre
- Cameras at every 60-metre
The decision to build a strategic tunnel below the Rohtang Pass was taken on June 03, 2000, when late Atal Bihari Vajpayee was the Prime Minister. The foundation stone for the access road to the South Portal of the tunnel was laid on May 26, 2002. However, till the year 2013-14, the work was so neglected that only 1,300 metres — less than 1.5 km — of the tunnel could be built.
The breakthrough from both ends was achieved on October 15, 2017. On December 24, 2019, on the eve of the birth anniversary of former Prime Minister Vajpayee, the Union Cabinet decided to name the Rohtang Tunnel as Atal Tunnel to honour his contribution.
Significance of the tunnel
- It would expedite the economic progress of one of the most sensitive border regions of the country.
- Farmers, horticulturalists and youth will now have easy access to Delhi and other markets.
- Atal Tunnel is the first step towards providing all year connectivity to Ladakh. It has the potential to link Ladakh to Manali and Chandigarh throughout the year because it would bypass Rohtang Pass, which is covered with snow in the months of winter.
- The tunnel will also help the security forces in ensuring regular supplies and in patrolling as it provides year-long connectivity to the border areas. It will also save the whole day for troops and supplies as they move towards forwarding posts.
- An engineering marvel, it will give a major impetus to India’s border infrastructure and strategic command.
- It will enhance tourism as livelihoods in the tourism sector of the residents in Lahaul Valley and Ladakh would increase.
A few facts about this engineering marvel
- The feasibility study for the Atal Tunnel was first done in 1990. The foundation stone for the access road to the south portal of the tunnel was laid on May 6, 2002. The first blast took place in 2010 and the last blast in 2017. The tunnel was constructed using drill and blast NATM (New Austria Tunnelling Method) techniques.
- The 9.02 km long tunnel connects Manali to Lahaul-Spiti valley throughout the year. Earlier the road remained impacted for about six months every year owing to snowfall. The tunnel is built with ultra-modern specifications in the Pir Panjal range of Himalayas at an altitude of 3000 metres (10,000 feet) from the Mean Sea Level (MSL).
- It reduces the road distance by 46 km between Manali and Leh and the time by about four to five hours.
- 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 horseshoe-shaped, single tube double lane tunnel with a roadway of 8 metres. It has an overhead clearance of 5.525 metres. Also, it is 10.5-metre wide and has a 3.6 x 2.25 metres fire-proof emergency egress tunnel built into the main tunnel itself. There are 18 egress tunnels where after every 500 metres there is an opening in case of emergency. If any fire incident happens so first thing is how the people trapped are to be rescued. For that there is an entry at every 500 metres.
- Atal Tunnel has been designed for traffic density of 3000 cars per day and 1,500 trucks per day with max speed of 80 km/hr. It has the state of the art electromechanical system including semi transverse ventilation system.
- The Border Roads Organisation (BRO) worked relentlessly to overcome major geological, terrain and weather challenges that included the most difficult stretch of the 587-metre Seri Nalah Fault Zone. The breakthrough from both ends was achieved on October 15, 2017.