Atal Tunnel: The strategic, engineering marvel

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This is a national asset that’s not just strategically important, but is also going to make India proud on the world stage, while opening the floodgates for the as-yet untapped immense tourism potential of Lahaul-Spiti region.


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  PM Narendra Modi flags off a bus with first batch of 15 passengers to cross Atal Tunnel from its north portal in Sissu, Lahaul valley, to the south portal in Rohtang.

The Rohtang tunnel, now renamed as Atal Tunnel, is the longest highway tunnel in the world above 10,000 feet. It will reduce the distance between Manali and Leh by 46 km and the travel time by four to five hours.
The 9.02-km tunnel is built with ultra-modern specifications in the Pir Panjal range of Himalayas in Himachal Pradesh at an altitude of 3000 mtrs (10,000 Feet) from the Mean Sea Level (MSL).
It is the longest highway tunnel in the world, which connects Manali to Lahaul-Spiti valley throughout the year. Earlier, the valley was cut off for about 6 months each year owing to heavy snowfall.
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 Work in progress
It has been designed for traffic density of 3,000 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, SCADA controlled firefighting, illumination and monitoring system.
The horseshoe shaped, single-tube, double-lane tunnel has many firsts. It is also the country's first tunnel to have an escape tunnel within the main tunnel because of the topography. This is also the first tunnel to deploy the Rowa flyer technology, which allows engineers to work at inverted levels.
Once thrown open, the tunnel will provide all-weather connectivity to remote border areas of Himachal Pradesh and Ladakh which otherwise remain cut-off from the rest of the country for about six months during winters.
The tunnel provides a telephone facility on every 150 metres, fire hydrant on every 60 metres, emergency exit on every 500 metres, turning cavern on every 2.2 km, air quality monitoring on every one km, broadcasting system and automatic incident detection system with CCTV cameras on every 250 metres.

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It will also save crores of rupees in transport costs in the long run.
The historic decision to construct the 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.
The Union Cabinet met under the chairmanship of Prime Minister Narendra Modi on 24th December 2019 and decided to name the Rohtang Tunnel as Atal Tunnel to honour the contribution made by the former Prime Minister.
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.
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The tunnel has been completed in a span of 10 years.
The opening of the Atal Tunnel at Rohtang is expected to give a fresh impetus to tourism and winter sports in Lahaul. Residents are hoping to see economic development in the region after this.
“Tourist season here currently lasts only a few months beginning June. We’re hoping it will now run from April till November at least. In peak winters, however, tourism is unlikely due to heavy snow and extreme cold,” an Indian Express report quoted Tashi Karpa, who runs a hotel in Keylong.
Quoting the state tourism department data, the report said Lahaul-Spiti district records the least tourist footfall among the 12 districts of the state. In 2018, 1.33 lakh tourists visited the district while more than 30 lakh did so in neighbouring Kullu.
Lahaul usually acts as a transit camp for travellers headed to Ladakh as it lies on the Manali-Leh route, but is now expected to become a tourist destination due to easier access from Manali.
Residents say Lahaul has the potential to host international winter sports competitions because it stays covered in snow for six months, and has suitable slopes and climatic conditions. In fact skiing and snowboarding competitions among the residents are reportedly held here every year during the Yeti Festival in winter.
The Rohtang Pass highway tunnel, marvel of engineering motorways, will now give impetus to more road infrastructure projects in the region.
The Rohtang tunnel alone is not enough to provide the Manali-Keylong-Leh axis an all-weather link as the tunnel is going to help only civilians of Keylong, according to agency reports quoting BRO officials.
The all-weather road to forward areas requires more tunnels like Rohtang Pass, either at Shinku La or at least three passes located on the original 475-km Manali-Leh road for round-the-year connectivity.
From Keylong, the district headquarters of Lahaul-Spiti, the road travels further to Leh via Darcha, some 170 km from Manali.
From Darcha, where the BRO has just completed the 360-m long longest steel truss bridge, one road bifurcates towards Shinku La (pass), the shortest route that traverses the remote Zanskar region towards Padum, some 30 km from Leh, and another towards the windy Manali-Leh highway.
"Other three high-altitude mountain passes that lie between Keylong and Leh still remain snowbound for at least six months in a year that make the highway totally standstill," he said.
After completion of the Rohtang Pass tunnel, the focus of the Indian government now shifts towards the construction of the Shinku La tunnel owing to the strategic significance of the third route to Ladakh, a shorter one.
Officials say the focus now is on constructing the strategic 13.5-km-long Shinku La tunnel, the shortest, safer and the third alternative corridor for the armed forces for forward areas of Union Territory of Ladakh.
Currently, the troop movement towards Ladakh is by two routes -- the 434-km Srinagar-Kargil-Leh via Zojila Pass and the 475-km Manali-Leh highway that passes through the Rohtang Pass. But they remain cut off from the rest of the country for over six months due to heavy snowfall.
The 297-km long Darcha-Nimmu-Padum road has been identified as the third strategic alternative to Ladakh in wake of the threat from Pakistan and China. The double lane road is under construction and likely to be completed by 2023, officials say.
The BRO is also studying the feasibility of constructing a tunnel beneath the 13.5-km-long snow avalanche-prone Shinku La like the Rohtang tunnel to avoid the majestic pass.
The tunnel beneath Shinku La is expected to further drastically reduce the distance between Manali and Leh.
The Manali-Leh route is 475 km, while the Manali-Darcha-Padum-Leh road is 444 km.
Currently, the National Highways and Infrastructure Development Corp Ltd is preparing the detailed project report of the Shinku La tunnel that will link Himachal Pradesh with Ladakh.
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For Kargil, the troop movement from Manali is via Leh that is 700-km long.
With the construction of the Darcha-Nimmu-Padum road through the Shinku La tunnel, the distance between Manali and Kargil will be reduced to 522 km.
On completion of the Shinku La tunnel, the Manali-Kargil highway will remain open throughout the year, the Ministry of Road Transport and Highways said in a statement last week.
The strategic importance of the Manali-Leh link was realised by the government when Pakistan tried to cut off the Srinagar-Leh road during the 1999 Kargil conflict, in a bid to restrict road access to Ladakh.
With a round-the-year road link to tribal areas, the region will witness a huge influx of tourists not only for nature-based activities but also for visiting ancient Buddhist monasteries,
  •  Atal Tunnel is constructed at an estimated cost of ₹3,500 crore
  •  TRhe construction consumed 14,508 metric tonnes of steel, 2,37,596 metric tonnes of cement, and excavated out 14 lakh cubic metres of soil and rocks
  •  The drill and blast technique was used for excavation and the New Austrian Tunnelling method for construction
  • The South Portal (SP) of Atal Tunnel is located at a distance of 25 Km from Manali at an altitude of 3060 Mtrs, while the North Portal (NP) of the tunnel is located near village Teling, Sissu, in Lahaul Valley at an altitude of 3071 Mtrs
  •  It has an overhead clearance of 5.525 Mtrs. It is 10.5-metre wide and has a 3.6 x 2.25 Mtrs fire proof emergency egress tunnel built into the main tunnel itself.
  •  The overhead clearance of the tunnel is 5.525 metres. The width of the tunnel is 10.5 metres.
  • A fire-proof emergency exit tunnel has also been built within the main tunnel itself. This emergency tunnel is 3.6 metres by 2.25 metres.
  • Atal Tunnel has been designed to handle the maximum speed of 80 km per hour.
  •  Atal Tunnel has also been equipped with a state-of-the-art electromechanical system. It contains a SCADA-controlled illumination, monitoring as well as fire-fighting system, and semi-transverse ventilation system.
  • Authorities have also ensured that the tunnel remains safe, with several safety features put in place. Tunnel entry barriers have been placed at both the portals, while arrangements have been made for telephone connections to be available every 150 metres for an emergency.
  •  The Rohtang tunnel also contains an auto incident detection system, and CCTV cameras have been fitted every 250 metres.
  • The provision for air quality monitoring has been placed at every 1 km. Evacuation lighting and exit signs are also present every 25 metres.
  •  A broadcasting system has been put in place throughout the tunnel.