Valutazione dell'influenza delle caratteristiche superficiali dei materiali sul contatto ruota-rotaia

This study, carried out in collaboration with the Tokyo Railway Technical Research Institute in Tokyo, deals with the evaluation of the effective wheel-rail contact area, that is the part of the contact ellipse where is effectively concentrated the mutual exchange of forces and thermic gradients between the two coupled surfaces; this contact area strongly influences, as known, the adherence coefficient (particularly in wet condition). The research is specifically finalised to establish in which way the different surface roughness level modifies the effective contact area dimension and the way this area raises at the increase of the applied external load. The experimental test results show a significant increase of the effective contact area at the surface roughness decrease, while no important variation has been recorded as far as the contact ellipse shape and dimension are concerned. Some possible practical consequences on railway operation, deriving from laboratory results, are finally proposed.