the western line to Nyala (1959) in Darfur Province, and a southwesterly branch to Wau (1961), southern Sudan's second largest city, located in the province of Bahr el Ghazal. That essentially completed the Sudan Railways network, which totalled about 4800 route km in 1990. There were small later extensions from Abu Gabra to El Muglad (52 km in 1995), El Obeid to the El Obeid refinery (10 km), and El Ban to the Merowe Dam (10 km.]. Source: Diesel traction Conversion of Sudan Railways to diesel traction started in the late 1950s, but a few mainline steam locomotives continued in use in 1990, serving lines having lighter weight rails. Through the 1960s, rail essentially had a monopoly on transportation of export and import trade, and operations were profitable. In the early 1970s, losses were experienced, and, although the addition of new diesel equipment in 1976 was followed by a return to profitability, another downturn had occurred by the end of the decade. The losses were attributed in part to inflationary factors, the lack of spare parts, and the continuation of certain lines characterized by only light traffic, but retained for economic development needs and for social reasons. A number of South African diesel locomotives are in use in Sudan. Downturn The chief cause of the downturn appeared to have been loss of operational efficiency. Worker productivity had declined. For example, repair of locomotives was so slow that only about half of the total number were usually operational. Freight car turnaround time had lengthened considerably, and the reported slowness of management to meet growing competition from road transport was also a major factor. A former official in the Sudan train union blamed Gaafar Nimeiry's attempts to crush the unions (who had organised numerous strikes on the railway) by firing 20,000 well qualified employees from 1975-1991. The road system, although generally more expensive, was used increasingly for low-volume, high-value goods because it could deliver more rapidly—2 or 3 days from Port Sudan to Khartoum, compared with 7 or 8 days for express rail freight and up to two weeks for ordinary freight. In 1982, only one to two percent of freight (and passenger) trains arrived on time. The gradual erosion of freight traffic was evident in the drop from more than 3 million tons carried annually at the beginning of the 1970s to about 2 million tons at the end of the