Kolkata metro will become the first railway service in the country to run an underwater train. The east-west corridor phase of Kolkata Metro has encapsulated a part of the Hoogli river too. Instead of riding the train through a bridge, the authorities have innovated a way to run an underwater train through a tunnel through the river.
India’s first underwater river tunnel is ready for inauguration. Kolkata Metro Rail Corporation (KMRCL) has been developing east-west metro corridor, which is 16.6 km long. Of this total track, 520m track will be under the Hoogli River. The first phase of this track which is a 5 km long part of the total east-west corridor stretches between Salt Lake sector 5 and Salt Lake Stadium & is likely to be inaugurated on Thursday, 24th October 2019. This is the day when in 1984, the country’s first metro in Kolkata – the north-south route was flagged off.
This will be India’s first railway track to run underwater. The tracks are built more than 33 metres below the river bed. The track will connect Kolkata to Howrah.
While, the 1st phase of East-West corridor of Kolkata Metro was scheduled to be completed and become operational by 2012, land acquisition, slum relocation and route alignment problems deferred the project.
It will take about 60 seconds for the train to pass through the 500m long tunnel, thus reducing a lot of time for the commuters, who would otherwise be taking ferries on the river, taking 20 minutes. Further, if you are in a mood to take a taxi, the brutal traffic on the Howrah bridge take hours to clears during busy hours.
Apart from being the fast commuting method, the underwater metro tunnel has other marvels to offer too. For the engineers, preventing water leakage in the tunnel was the biggest challenge. The structure is made using 1.4 m wide rings and made up of entire composed concrete brought directly to the location. The concrete has been placed with a special gasket in between, which swells 5 times, as soon as it comes in contact with water, to prevent water leakage. The width of the river Hoogli (Subsidiary of Ganga) is 500m here. The tunnel is built 13m below the river bed, with tracks going down 33m. The diameter of the tunnel is 5.8m.
Further, to fight the situations of emergency, Walkways have been built and enough fire alarms have been set up. Further, for a smooth process for firefighters to enter the tunnel, separate arrangements have been made so that the passenger evacuation route does not collide with the emergency route.
Further, the tunnel is built two way, so that the two trains, coming and going, will not collide at any time, thus ensuring smooth movement. Further, there have been several other challenges including keeping the old building intact during the construction, because the construction site was close to much old building which aged backed to the British era.
As a precautionary measure, authorities evacuated many buildings before construction began and moved more than 500 people temporarily in hotels. Apart from this, it was not at all easy for the 1000+ workers to survive in the tunnels as the temperature beneath rarely went below 50-degree Celcius. The hot surrounding with the lack of oxygen supply made it hard for workers to work in the tunnel.
This will be the first big underwater tunnel under any river in India.
As per a report by Times of India Prime Minister Narendra Modi will be present in Kolkata on the day and Chief Minister Mamata Banerjee also expected to be in the capital city on the day. The inauguration of the first phase of the east-west corridor is likely to take place on 24th October.
The first phase of the East-West corridor, which was originally scheduled to become operational by 2012 faced issues regarding land acquisition, slum relocation and route alignment, delaying the project to 2015 & eventually to 2018-19. Once the route becomes operational, it will handle a lot of commuters daily on the Kolkata-Howrah route.