Chicago City Railway Co. - served Chicago's south side.
Chicago Railways Co. - served Chicago's north and west sides.
Calumet & South Chicago Railway Co. - served Chicago's far south side.
Southern Street Railway Co. - small company operating primarily on Cermak Road.
Yerkes later formed several additional streetcar companies in the outlying areas on Chicago's north and west sides, feeding into his existing systems. In 1899, those companies were combined into the Chicago Consolidated Traction Co. And in 1899, the North Chicago Street Railroad Co. and the West Chicago Street Railroad Co. were merged into the Chicago Union Traction Co. By 1910, those companies had all been consolidated into the Chicago Railways Co.
In 1893, Yerkes moved into the elevated railroad field as the principal backer in the incorporation of the Northwestern Elevated Railroad Co. Service began in 1900. In 1894, he acquired control of the Lake Street Elevated Railroad Co., and also formed the Union Elevated Railroad, which built the "Loop" which opened in 1897.
In 1897, Yerkes acquired the Suburban Railroad Co., whose streetcars had served the western suburbs and connected with the competing Metropolitan West Side Elevated Railroad Co. After gaining control, the Suburban Railroad Co. routes were changed to connect instead with his Lake Street Elevated Railroad.
In 1901, Yerkes sold nearly all of his transit holdings in Chicago and moved to London, where he worked on expanding that city's subway system. He did not sell the Suburban Railroad Co., which remained in his estate until 1913 when it went to the Chicago and West Towns Railway Co. Yerkes died in 1905. His name lives on with the Yerkes Observatory, located in Williams Bay, Wisconsin, and affiliated with the University of Chicago. Yerkes Observatory celebrated its 100th anniversary in 1997, and is still home to the world's largest refracting telescope (40 inch lens).
Northern Electric Railway Co. - 1894 to 1902. Operated near Cicero Ave. from Lake St. to North Ave., and via North Ave., Central Ave., and west on Grand Ave. to Austin Ave. The line was interrupted at the Milwaukee Road tracks south of Grand Ave. and Central Ave., with passengers required to walk across the tracks and change cars.
General Electric Railway Co. - 1896 to 1901.