Also bear in mind that the ATS (the inter terminal landside train) at ORD isn't running again until the Winter US Holiday season:
https://www.flychicago.com/business/...px?newsid=1572
I have been through Chicago twice this year. Once I walked more or less straight onto one of the shuttle bus replacements from T5, the other time I had to wait over an hour as the queues were horrendous.
BM