The Dan Ryan Branch opened on September 28, 1969, and was paired with the Lake Street branch to form the West-South route, almost universally referred to as the Lake–Dan Ryan route. It operated over the Lake Street and Wabash Avenue sides of the Union Loop. This "interim" service was created mainly for the purpose of providing through service between the west side and the south side in anticipation of the 1968 Loop Subway Project. When the controversial subway project was cancelled in 1979, the Lake-Dan Ryan service remained and lasted for 24 years.