The street railway system began in Chicago around 1858 with horse-powered cars. In 1880 cable cars began replacing this slow and expensive method, and in the late 1880s new companies sprang up using the new electric "trolleys". The older companies soon followed. The 1890s and early 1900s saw the consolidation and reorganization of the numerous companies until the Unification Ordinance of 1913, which stipulated that all would come under the management of a single company, the Chicago Surface Lines (CSL). The CSL became the largest street railway system in the world.
Blueprints and tracings of the Chicago surface railway system,1886-1926. The 15 blueprints are from the Chicago City Railway Company and the West Chicago Street Railroad Company (1891). The 192 tracings include plans of cars for Chicago Railway (1904-1916), Lake Street Elevated Railroad (1895), and the Chicago City Railway (1908-9). Plans of switches, track layouts, power stations, and other railroad structures for a number of companies, most being for the West Chicago Street Railroad Company (1888-1892). Also a single drawing from the Pennsylvania & West Virginia Railway, 1948.
Chicago Surface Lines Drawings, 1880-1948, Archives Center, National Museum of American History