HiL pantograph tests with a realistic catenary model including overlap section

For pantograph-catenary systems, Hardware-in-the-Loop (HiL) testing represents a valuable tool to partly replace expensive and logistically complex in-line tests. However, the regulatory acceptance of such methodologies requires excellent accuracy while keeping real-time performance. This paper proposes a methodology to perform HiL pantograph tests utilising a high-fidelity finite element catenary model that incorporates overlap sections and the simultaneous interaction of a pantograph with two contact wires through a penalty-based formulation. Without loss of generality, the Italian C270 overhead line and the ATR 95 pantograph have been chosen to exemplify the proposed method. To achieve the real-time execution required for HiL environments, the conventional PACDIN software algorithm was modified introducing five simplifying hypotheses. These actions successfully reduced the computational cost while maintaining a high accuracy. System stability and force tracking were ensured using an interaction mass and an LQG controller, mitigating the effect of delays and actuator dynamics. The proposed methodology was validated in a two-stage process: first, by demonstrating good agreement between the real-time algorithm and conventional solvers, then, by comparing HiL results with experimental measurements obtained from an instrumented pantograph during in-line tests. The results show a relative difference in the contact force standard deviation of only 6.2%, falling within the acceptable limits defined by the EN 50318 standard. This work represents a significant milestone in developing robust HiL tools capable of simulating complex overhead contact line discrete features with the accuracy required for high-speed railway applications.