Kolkata: KMC’s next big challenge after cutting off supply through the damaged water pipeline is to repair the damaged pipe, which is 7 metres underground, without disturbing railway services.Sources said the 1,800 mm damaged pipe is large enough to allow a man to enter, detect the location and scale of the leak and do repairs. A leak in the same place in 2010 was repaired by engineers going down through a pit some distance away from the leak and then walking inside the pipeline to reach the point of the leak. But those pits could have been damaged during construction of the new Tala Bridge between 2020 and 2022.Another option before engineers is to dig a new pit, closer to the location of the leak. But it will need convincing railway officials that there will not be any disturbance on the tracks. Officials said as per their estimation, the leak is located between tracks used for daily passenger services and ones that are used by trains headed to the Chitpore yard for maintenance, loading and unloading of goods.The tracks, near the point of the leak, are between Kolkata and Tala stations of Circular Railway. Services of Circular remained shut for a few days at the peak of the leak last week when the tracks were waterlogged. Trains headed to Sealdah North section also run via these tracks.“The waterlogging led to fears that there could be subsidence of the tracks. If water remained logged on the railway tracks for several days, the compactness of the soil underneath would have reduced. This, in turn, could have resulted in the soil moving away and leading to subsidence on the railway tracks. Timely intervention has not led to such a situation,” said a KMC official.“We can now dig a new pit on the ground to directly reach the leak. It will be close to the railway tracks, but we will take adequate precautionary measures so that tracks are not disturbed in any way. We can do sheet piling to prevent erosion and subsidence, and ensure that the tracks remain firm in their place,” said an engineer.Sheet piling is an earth retention and excavation support technique that uses long, thin, interlocking structural sheets driven into the ground to form a continuous barrier against soil and water.KMC officials said nothing had been fixed yet, and all options were under consideration. “We will have to write to Eastern Railway to intimate them and seek their consent for repairs. We have to factor in their opinion while choosing the best possible option for repairs of the damaged pipe,” said sources.The damaged 1,800 mm steel pipe was built during the British era, said KMC officials.
