WN 209 then DL 1940 at Denver
St Louis → Denver → Salt Lake City
Timetable, Denver time
18:50WN 209 from St Louis at the gate
16:00DL 1940 to Salt Lake City leaves the gate
21 h 10 apart on the timetable, overnight
DL 1940 leaves 21 h 10 after WN 209 arrives on the timetable: more than half a day, so not a connection we count.