Indian Railways will soon start its largest track renewal exercise, targeting the replacement of 8,000 km of old and depleted lines on trunk routes at an estimated cost of Rs 10,000 crore and overhauling the entire signalling network to improve safety.The railways hopes this will reduce the number of derailments by 50 per cent in the next two years. It will invite global tenders for the procurement of rails. “This length of 8,000 km would be taken starting next financial year and we would wrap up the work by the end of FY20. These are the high-density tracks for Indian Railways. We’re working towards an accident-free network,” a top government official said. Indian Railways replaces about 2,500 km of old tracks on an average every year. In the current financial year, it’s renewing almost 3,000 km. It has a total route network of 64,000 km. The ministry is also looking at bringing in advanced signalling systems to allow trains to operate at higher frequency even on busy routes. “A new signalling technology will soon be introduced in railways. It will be the biggest-ever technology upgrade,” the official added.Indian Railways is seeking almost Rs 15,000 crore from the finance ministry in the next budget for its safety fund and related works. This money will be spent on renewal of tracks, repairing of old bridges, upgrading the signalling network and removing unmanned level crossings.The finance ministry allotted about Rs 5,000 crore for the safety fund this financial year. Rail Board chairman Ashwani Lohani recently said that the number of train accidents has reduced.He said the railways was in the process of filling 1lakh posts related to safety works in the national transporter. “Train accidents have been continuously decreasing from 135 in 2014-15 to 107 in 2015-16 and down to 104 in 2016-17,” minister of state for railways Rajen Gohain recently said in the Rajya Sabha.