NEW DELHI: India's ambitious project to redevelop 400 railway stations through private sector investment will be the largest public-private-partnership (PPP) project in the world, Railway minister Suresh Prabhu said on Friday. However, Prabhu did not share the total project cost but he said no project of such proportion has been ever undertaken in the world.As per rough estimates, there would be an average redevelopment cost of Rs 100 crore per station.As a part of the station redevelopment project, railways will have online bidding of stations and private players would be allowed to earn revenue through commercially exploiting the real estate.Speaking at the CII PPP summit, Prabhu said no railway in the world can survive on just ticketing revenues. "In long term we should target around 30-40% revenue from non-core business like commercial exploitation of our assets, Prabhu said.He also said railways will soon have a sectoral regulator.