Abstract: Using the MJP-30A rolling wear and contact fatigue test rig, the optimum coating amounts of two kinds of water-based friction modifiers (FM1 and FM2) were studied. The effects of FM1 and FM2 on wear and damage of wheel and rail under the optimum coating amount were analyzed. The results showed that the optimum coating amounts of FM1 and FM2 were 14 μl and 8 μl, respectively. The wear rates of wheel/rail specimens with the presence of FM1 medium were only 23% and 41% of those in dry condition. The wear rate of wheel specimen with the presence of FM2 medium was slightly higher than that in dry condition, and the wear rate of rail specimen was 64% of that in dry condition. Under the dry condition or with the presence of FM2 medium, peeling, spalling and obvious fatigue cracks appeared on the wheel and rail surfaces. On the cross sections of wheel and rail specimens, multi-layer cracks, branch cracks and subsurface cracks appeared. With the presence of the FM1 medium, the wheel and rail specimens were damaged slightly. The slight peeling and pitting appeared on the surface and a small number of single-layer micro cracks appeared on the cross sections. FM1 could effectively reduce the wear and damage of wheel and rail.