Head checks (HCs) at rail gauge corner and shoulder were inspected by X-ray computed tomography scan technology (CT scanning). The boundary points at the mouth and tip of the real HCs were obtained by grid method to establish the numerical model of the real HCs. Taking the HCs at the gauge corner and shoulder of the high rail in a heavy-haul railway sharp curve with traffic gross tonnage of about 62 MGT as an example, this study analyzed the transformation of the stress intensity factors (SIF) at the tips of multiple HCs and the effect of the crack number on them. The results show that the HCs are more likely to extend with an orientation of 10°- 30° with respect to rail longitudinal direction， always less than 0 under any condition, indicating that the crack is not extended by Model I (opening). HCs are greater than 0, and the trend of is reduced from positive to negative along rail gauge corner to crown when contact patches pass by the crack central mouth, which shows that the HCs is mainly composed of Model II (sliding) and III (tearing). The existence of multiple HCs will promote their propagating as Model II and III, and the influence will be enhanced with the increase of crack number. Compared with the single crack, SIFs at the tips of multiple cracks will increase, and the SIFs at the tip of the middle crack will be greatly influenced by adjacent cracks. Therefore, at least 3 cracks are recommended in crack propagation modeling for crack prediction.