The CTA has posted warning notices. "Service Changes Effective February 7," they announce. Below this headline is a list of express bus routes to be canceled, followed by a list of local routes that will see less frequent service. Some of these routes are asterisked.
The asterisk is explained in a footnote. It says, "These routes only have frequency reductions during periods when the eliminated express routes they parallel are not running."
So when the eliminated express routes are running, it's business as usual.