The final spur of railway construction began in the 1950s.[7] It included extension of the western line to Nyala (1959) in Darfur Province and of a southwesterly branch to Wau (1961), southern Sudan's second largest city, located in the province of Bahr el Ghazal. This essentially completed the Sudan Railways network, which in 1990 totalled about 4800 route km[2] [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)[8]].