The condition monitoring of an overhead contact line (OCL) is investigated by developing an innovative monitoring system for a pantograph on an electrical multiple unit of a regional line. Kinematic and dynamic modelling of the pantograph is conducted to support the designed monitoring system. The modelling is proved through rigorous test-rig experiments, while the proposed methodology is then validated through extensive field tests. The field tests serve a dual purpose: First, to validate the monitoring system using benchmark measurements of the tCat (R) trolley, and second, to assess the reproducibility of measurements in a realistic case. This paper presents the OCL monitoring system developed in the framework of the H2020 project SIA. The accuracy of our results is not far from that of other commercial systems, with just 12 mm of absolute error in the height measurement. Therefore, they provide reliable information about trends in various key performance indicators (KPIs) that facilitates the early detection of failures and the diagnosis of anomalies. The results highlight the importance of model calibration and validation in enabling novel health monitoring capabilities for the pantograph. By continuously monitoring the parameters and tracking their degradation trends, our approach allows for optimized scheduling of maintenance tasks for the OCL.

Twin-disc tests present some limitations for wheel-rail wear characterization such as the obtained contact patch and the error for very low creepages. In this work, creepage phenomena are investigated ranging from 0.12% to 2.45%. To improve the fitting of experimental tests with the theoretical adhesion curve, a modification of the FASTSIM algorithm is proposed. A linear correlation has been found between wear and the slip area including the non-linear zone. Normalized weight losses and wear rates are similar for all tested creepages. Applying this relationship, identified for delaminative wear by surface and metallographic characterization, it is possible to calculate wear for low creepages at wheel-rail contact from twin-disc tests, which should be close to the satu-ration of the friction coefficient.

In this work the influence of considering wheel-rail contact creepages on fatigue crack growth rates due to Rolling Contact Fatigue (RCF) is studied. For this purpose, the FASTSIM algorithm, which considers the moving complex pressure distribution with slipping and adhesion zones of the wheel-rail contact patch, has been implemented in Abaqus using FORTRAN code subroutines. The developed methodology has been validated with a 60E1 rail profile model which uses XFEM, by comparing the obtained Stress Intensity Factors (SIFs) and sub-surface shear stresses with numerical results available in the literature. Finally, the RCF crack propagation analysis of a 60E1 rail profile with different contact conditions has been performed using the XFEM. The obtained results justify the necessity of considering contact creepages on contact shear stresses for crack growth analysis.

Rolling contact fatigue (RCF) is a common cause of rail failure due to repeated stresses at the wheel-rail contact. This phenomenon is a real problem that greatly affects the safety of train operation. Preventive and corrective maintenance tasks have a big impact on the Life Cycle Cost (LCC) of railway assets, and therefore cutting-edge strategies based on predictive functionalities are needed to reduce it. A methodology based on physical models is proposed to predict the degradation of railway tracks due to RCF. This work merges a crack initiation and a crack growth model along with a fully nonlinear multibody model. From a multibody assessment of the vehicle-track interaction, an energy dissipation method is used to identify points where cracks are expected to appear. At these points, crack propagation is calculated considering the contact conditions as a function of crack depth. The proposed methodology has been validated with field measurements, conducted using Eddy Currents provided by the infrastructure manager Network Rail. Validation results show that RCF behavior can be predicted for track sections with different characteristics without the necessity of previous on-track measurements.

A full explicit FEM simulation of wheelset passing through switch panel is presented. The real 3D geometry of the switch panel is used, both vertical and lateral response are taken into consideration. The dynamic interaction is analysed and it is found that the damage mechanism on the switch blade and stock rail is a complex interaction of wear, fatigue and impact, which can be well described by explicit FEM simulation. Parametric analysis of running speed, traction coefficient and the friction coefficient between switch blade gauge surface and wheel flange indicate that decreasing running speed can help to reduce the damage on switch panel. The traction coefficient has little influence on the maximum impact response, but a higher traction coefficient is beneficial for eliminating the dynamic response after the maximum impact response point. The influence of the friction coefficient on the dynamic impact response is not significant, but a lower friction coefficient is favourable for decreasing the wear damage on the switch blade and increasing running safety. This work can provide a good understanding of the interaction on switch panel and give theoretical support for maintenance and improving the design.