During the 1850s and 1860s additional plant species were introduced from Australia by the British authorities. Notably rooikrans to stabilise the sand of the Cape Flats to allow for a road connecting the peninsula with the rest of the African continent and eucalyptus to drain marshes. In 1859 the first railway line was built by the Cape Government Railways and a system of railways rapidly expanded in the 1870s. The discovery of diamonds in Griqualand West in 1867, and the Witwatersrand Gold Rush in 1886, prompted a flood of immigrants to South Africa. In 1895 the city's first public power station, the Graaff Electric Lighting Works, was opened. Conflicts between the Boer republics in the interior and the British colonial government resulted in the Second Boer War of 1899–1902, which Britain won. From 1891 to 1901, the city's population more than doubled from 67,000 to 171,000.