Sri Lanka, Aug. 19 -- For the first time in the history of Sri Lankan Railways, the Asian Development Bank has approved a loan worth 160 million dollars to modernize the operations and improve the efficiency of Colombo suburban railway service, Transport and Civil Aviation Minister Arjuna Ranathunga said.The agreement with regard to this is scheduled to be signed tomorrow at the Finance Ministry.Addressing a media conference held yesterday at the Temple Trees, Minister Ranthunga said that the loan has been approved for the implementation of some sub-projects and 36 purchases. According to the Minister Railway tracks from Maradana to Avissawella on Kelani Valley Line, Maradana to Rambukkana on Main Line, Colombo Fort to Kalutara South on C...