UA 4592 then CA 3174 at O'Hare
St Louis → Chicago → Guangzhou
Timetable, Chicago time
19:05UA 4592 from St Louis at the gate
13:40CA 3174 to Guangzhou leaves the gate
18 h 35 apart on the timetable, overnight
CA 3174 leaves 18 h 35 after UA 4592 arrives on the timetable: more than half a day, so not a connection we count.