Well, I'm not sure that's likely. But it does give me a chance to post my RER/S-bahn fantasy for Chicago.
Begin with 30-minute service on four lines, through-routed via the St. Charles Air Line and Union Station through tracks. This only requires three new turnouts. In Phase 2, an expensive new Munich-style tunnel under Clark and Chicago Ave. would give access to the heart of the Loop. Transfer stations (with timed meets) where the downtown routings cross give passengers their choice of Central Loop–River North or West Loop. O’Hare access is most expedient today via CP/NCS but may be more practical long-term via MD-W.