ZH 8904 then 9C 8836 at Guangzhou
Zhengzhou → Guangzhou → Shanghai Hongqiao
Timetable, Guangzhou time
13:55ZH 8904 from Zhengzhou at the gate
10:559C 8836 to Shanghai Hongqiao leaves the gate
21 h apart on the timetable, overnight
9C 8836 leaves 21 h after ZH 8904 arrives on the timetable: more than half a day, so not a connection we count.