Originally Posted by DSpivack
Huh? The Red Line has always run on the Dan Ryan tracks, no? It's not like they can switch over there.
No, when the Dan Ryan branch was built it was part of the Green Line, with trains running from 95th to Harlem in Oak Park via the Loop, whereas the North Side Red Line was paired with the Englewood/Jackson Park forks. They didn't switch them until they built the connection from the State Street Subway to the Dan Ryan branch in the early 90s when they built the elevated Roosevelt station.
CTA Map from 1991 shows the old configuration: http://www.chicago-l.org/maps/route/maps/1991map.jpg