Women in essential services. Women railroad workers take over the cars and maintenance of freight and passenger trains in the Southern Pacific Company yards at San Francisco

Originally a Spanish (later Mexican) mission and pueblo, it was conquered by the United States in 1846 and by an invading army of prospectors following the 1848 discovery of gold in its hinterland. The Gold Rush made San Francisco a cosmopolitan metropolis with a frontier edge. In early 1900s the city tried to remake itself into a grand and modern Paris of the West.