On tour in Sri lanka at present recording some great video of trains but only passenger so far. Are there any regular goods?
Apparently yes but good luck finding anything as the freight system was left to run down previously during the war and most things switched to road.
Remember in developing countries such as Sri Lankia and India, they have generally abandoned small and medium scale rail freight in favor of trucking despite it being slower. Indian Rail do not move anything smaller than rake load.
Just doing some googling, it was hard to find any references to SL rail freight outside their website. Nothing in Wiki.
i think fuel/oil is one of the main stays.