UA 5990 then BR 658 at O'Hare
Chattanooga → Chicago → Toronto Pearson
Timetable, Chicago time
11:54UA 5990 from Chattanooga at the gate
11:30BR 658 to Toronto Pearson leaves the gate
23 h 36 apart on the timetable, overnight
BR 658 leaves 23 h 36 after UA 5990 arrives on the timetable: more than half a day, so not a connection we count.