One of the plans being consider is to take rubbish to Puttalam, more than 130 kilometres north of Colombo where large pits from which limestone had been mined for cement manufacture could be filled.
"We estimate that three freight trains a day could take the entire city waste," Rohan Seneviratne, additional secretary of the ministry of defence and urban development said.
"The trains could run in the night."
Seneviratne said a study is being conducted to come up with a comprehensive plan to dispose of city waste and rail haulage plan was one of the available options.
Waste will be taken in special covered wagons. Already there was a rail track leading to the limestone mines.
It was estimated that about 150 acres of land would be needed for use as a landfill but there no space nearby.
Solid waste disposal in Colombo, Kotte, Dehiwala-Mount Lavinia and Kolonnawa is part of a larger 230 million US dollar project to boost drainage, prevent floods, build lakes, eco parks, sea and lakefront promenades with World Bank support.
Seneviratne said while there had been talk of setting up power plants burning municipal waste nothing concrete had come up despite an attractive rate of over 20 rupees a kilowatt being offered for developers.
He said Sri Lanka's solid waste was moist and was not deemed to generate sufficient heat to make a plant viable.