Pantograph-Catenary Dynamic Studies on Contact Wire Gradients Considering Aerodynamic Effects

On electrified railways the traction vehicles are powered via the pantograph-catenary interface. Electrification of legacy lines can prove a challenging aspect at level crossings, where the contact wire must manage height variations (gradients), while ensuring suitable current collection. Improvements on pantograph and overhead line equipment design can lead to a reduction on the impact these discrete features have on current collection performance, leading to higher operating speeds, cost savings and reduction in dewirement risk. Advanced computational tools can be used to model realistic overhead systems, and perform dynamic analyses of the pantograph-catenary interaction at critical areas. This enables a substantial reduction in the need for expensive line tests for verification or validation purposes. The main aim of this work is to assess pantograph-catenary dynamic performance at level crossings and overbridges, thus involving contact wire gradients, analysing different pantograph modelling approaches. The results demonstrate that both lumped-mass and multibody pantograph models are virtually non-sensitive to the contact wire height variations, presenting almost a constant contact force profile. However, the state-of-the-art multibody formulation that model the pantograph components with detail, can accommodate the non-linear characteristics of the real system, and include realistic external forces on each body, e.g., aerodynamic loads according to the pantograph opening range. These aerodynamic forces are particularly important when studying catenary gradients, as the pantograph experiences more drag and uplift forces as more extended it is. The developments presented here aid to reduce costs and de-risk rail electrification projects by enabling to understand the current collection performance at different train speeds and gradient steepness.