Investigations of the complex wear mechanisms of tram wheel tyres

Nowadays, the dynamic development of public transport is seen as one of the main ways to reduce exhaust emissions and, consequently, the greenhouse effect. One of the fastest-growing branches in this area is the building and evolution of tram lines. One of the conditions for the success of this transport method is the durability and reliability of the rail vehicles used. From a tribological point of view, friction behaviour and potential wear processes in the tram's rail-wheel contact is of special importance. Therefore, taking into account the specific structure of the tram wheel, the main goal of this study was to identify and characterise the wear mechanisms on the two areas most exposed: the running surface and the top surface of tyre flange. Furthermore, a detailed analysis of the surface topography of the worn surfaces of the tyres, with regard to the wear processes, was carried out. This part of the study included the measurements and analysis of the height parameters of the roughness and Abbott-Firestone curves (with their characteristics), both in accordance with the ISO 25178 standard. On this basis, it was found which parameters best characterise the evolution of the surface topography from the initial state to the worn one. As a consequence, those that have the potential to control the state of the tram wheels' tyres (mainly the level of wear) during operation are proposed.