This bachelor thesis addresses the measurement of adhesion and friction conditions at the wheel-rail interface, which fundamentally affect operational safety and the wear of railway tracks. An analysis of the current state of knowledge revealed that existing diagnostic tools are limited in their ability to accurately simulate real Hertzian contact pressures and are often structurally restricted to measurements on the rail head, thus neglecting the critically loaded guiding edge.
The main objective of this thesis is to design and construct a swappable, adjustable module for the existing portable BUT Rail tribometer. The proposed device is designed to enable detailed diagnostics of the coefficient of friction at six defined positions across the rail profile, while maintaining high structural rigidity, low weight for ease of field mobility, and ergonomic operation.
The problem was solved by designing a compact module that combines lateral displacement, vertical adjustment using a loading spring, and eccentric tilting of the entire measuring mechanism. The resulting structural design, with a total mass of 5.57 kg, reliably generates the required Hertzian contact pressures in the range of 0.7–1 GPa. The module successfully reaches all six defined measuring positions on standard flat-bottom rails and five positions on grooved rails, where the lowest position is limited by a structural collision with the rail body.
The proposed device significantly expands the diagnostic capabilities for friction mapping on real, irregularly worn rail profiles directly in the field. The detailed data obtained can contribute directly to the optimization of lubrication processes, effective wear reduction, and the overall extension of railway infrastructure service life, while the identified structural limits provide a clear basis for further development of the module.