How often do Tianjin subway security personnel change personnel?

Eight hours or nine and a half hours. According to Zhaopin's recruitment, the working hours of Tianjin subway security personnel are divided into morning shift and night shift. The working hours of the morning shift are from 6: 00 a.m. to 6: 00 p.m. 14 p.m. and the working hours of the night shift are from 6: 00 a.m. to 23:30 p.m. 14 p.m. So change people every 8 hours or 9.5 hours.