Chicago Passenger Railway Co. - incorporated 1883 as Chicago Horse and Dummy Railway Co., changed name in 1885.
Chicago West Division Railway & Tunnel Co. - incorporated 1888.
Chicago & Jefferson Urban Transit Co. - incorporated 1890.
Chicago Electric Transit Co. - incorporated 1892 as Jefferson Street Railway Co., name changed 1893.
Chicago North Shore Street Railway Co. - incorporated 1891 as Chicago & Evanston Electric Railway Co., name changed 1892. Acquired by North Chicago Electric Railway Co. in 1894.
Cicero & Proviso Street Railway Co. - incorporated 1889.
Evanston Electric Railway Co. - incorporated 1895.
North Chicago Electric Railway Co. - incorporated 1893.
North Shore Electric Street Railway Co. - incorporated 1894.
Ogden Street Railway Co. - incorporated 1891.
Chicago Railways Co. did not acquire that Chicago Consolidated Traction Co. trackage outside the city of Chicago. That suburban trackage went to the County Traction Co., newly formed in 1910. In 1913, the Evanston Railway Co. and the Chicago and West Towns Railway Co. were formed, acquiring the County Traction Co. operations in those respective areas.
In 1913, Chicago Railways acquired some trackage from the Suburban Railroad Co. The Suburban Railroad Co. was incorporated in 1895, and those operations in the suburbs were merged into the newly formed Chicago and West Towns Railway Co. in 1913.