The last suburban streetcar ran on the West Town's system in 1948, and Chicago's last streetcar operated June 22, 1958, on the Clark-Wentworth line. The street railways were the victims of their own high costs, increased use of the automobile, overregulation, and population migrations to the suburbs. The street railways, which suffered declining profits after 1907 because of city and state regulation, did not have the money to build new lines into the suburbs.
The bankrupt CSL system, which included all five of the streetcar companies, was acquired by the new Chicago Transit Authority in 1947 for a bargain-basement price of $75 million. Its investors lost $110 million on the transaction.