Prior to the construction of the connector at Cameron after the BN-ATSF merger in 1995, the Southwest Chief continued to Chicago on the ATSF Transcon:
Galesburg (Cameron) to Streator
Streator to Pequot
Pequot to Joliet
McCook to Joliet
Bridgeport to McCook
21st Street to Bridgeport
Chicago Union Station to 21st Street
Since the Cameron connector's construction, the train uses the former CB&Q entry to Chicago: