Take the train from Shijiazhuang to Xingtai and get off at the northbound railway station 100 meters. There is a bus to Renxian. If you take the express train, it can take you from Shijiazhuang to Renxian in two hours.
Hengshui is far from Renxian County, it takes 3 hours from Hengshui to Renxian County and 1.5 hours from Shijiazhuang to Hengshui.