Experimental Investigation on Sanding Effect of Rail Vehicles Under Low-Adhesion Conditions

To investigate the adhesion characteristics and sanding effect of rail vehicles on a contaminated rail surface, an innovative wheel/ring configuration test rig, named the PLS-Circulator, was employed. Based on the equivalence principle, the sanding condition relationship between the test rig and the field was first established. Then, extensive and quantitative experiments on the enhancement of rail vehicle adhesion in sanding conditions were conducted. The results show that the maximum adhesion coefficient of various media increases with an increase in the amount of sand, and the adhesion-enhancing effects gradually reach the threshold when the amount of sand is high. On the other hand, after a single application of sand, the increase in the adhesion coefficient gradually decreases over time, and the pattern of adhesion enhancement degradation varies in different media. It was found that oil is the most unfavorable condition, where the adhesion-enhancing effect deteriorates the fastest. The appropriate amount of sand on the PLS-Circulator is 0.3 g/m, corresponding to 4.8 g/m of sand in the field.