UA 4619 then BR 658 at O'Hare
Buffalo → Chicago → Toronto Pearson
Timetable, Chicago time
11:43UA 4619 from Buffalo at the gate
11:30BR 658 to Toronto Pearson leaves the gate
23 h 47 apart on the timetable, overnight
BR 658 leaves 23 h 47 after UA 4619 arrives on the timetable: more than half a day, so not a connection we count.