Abstract: The adhesion characteristics of wheel/rail by way of spraying sand under dry and water medium conditions were investigated using JD-1 wheel/rail simulation facility. Furthermore, the effect of sand size and sand volume on adhesion characteristics were focused on. The results indicate that Adding water under dry condition makes wheel/rail adhesion coefficient decrease drasticlly. Spraying sand can increase adhesion force.Under wet condition Spraying small sand can almost increase the adhesion coefficent to 50%, while spraying big sand can increase it to 65%. However, the adhesion coefficient increases slightly when sand is used under dry condition. The adhesion improving properties of sand mainly depend on diameter of sand particle and sand volume under water medium conditions. The sand with bigger diameter would appear better adhesion improving properties. when the sand volume is less than 50 g/min, the adhesion coefficient of wheel/rail increase with sand volume increasing. but when the the sand volume is more than 50 g/min, the adhesion coefficient is less than that when sand volume is 50 g/min.

Key words: Adhesion coefficient, Sand, Sand volume, Water medium