The first railway in Sudan opened in the 1870s paralleling the River Nile for about 54km south from Wadi Halfa. Intended as a trade route it was taken over for war purposes and twice extended, but abandoned in 1905. It was built to 3ft 6in (1067mm) gauge, which may have reflected the ambitious but never achieved dream of Cecil Rhode's for a line running the length of Africa from the Cape of Good Hope to Cairo, of which the Sudanese line would have formed part.
The next railway in Sudan was a military line opened in the 1890s between Wadi Halfa and Abu Hamad. It shared the 3ft 6in (1067mm) gauge of the earlier line so that equipment could be used in common. It was later extended to Atbarah and, after General Kitchener's defeat of the Mahdiyah, to Khartoum, which it reached at the end of 1899. The line was then turned over to commercial use and formed the basis of the present day network.
Further extensions to the 3ft 6in (1067mm) gauge network continued through the first half of the twentieth century, culminating in a network of around 4700km. Meanwhile, a group of 2ft (610mm) gauge lines opened in the 1920s for the construction of canals as part of the Gezira scheme had expanded into a 700km network serving agricultural communities at the confluence of the Blue Nile and the White Nile near Khartoum.
The railways went into an economic decline from the late 1960s / early 1970s and suffered further depradations during civil war from the 1980s. Work is in hand to rehabilitate and modernise the network, but continues to be hampered in some areas by civil unrest.
There were no international connections until 2011, when the creation of the Republic of South Sudan resulted in a new boundary on the Khartoum to Wåu line, between Babanusa and Aweil. A new international connection with Egypt would be formed by a proposed standard gauge line from Wadi Halfa to connect with Egyptian Railways at Aswan, replacing an existing ferry service along the River Nile. There is a further proposal for a new 300km standard gauge line from Nyala to the Chad border, where it would connect with a railway now under construction to the Chad capital, N'Djamena.
Flag image from CIA World Factbook