Transport in Sudan during the early 1990s included an extensive railroad system that served the more important populated areas except in the far south, a meager road network (very little of which consisted of all-weather roads), a natural inland waterway—the Nile River and its tributaries—and a national airline that provided both international and domestic service. Complementing this infrastructure was Port Sudan, a major deep-water port on the Red Sea, and a small but modern national merchant marine. Additionally, a pipeline transporting petroleum products extended from the port to Khartoum.