The sliding contact between the pantograph-catenary interface should remain uninterrupted to ensure the supply of electric power to railway vehicles. The resulting contact forces must also be within tight tolerances to avoid inducing damage on the assets and keep acceptable wear rates. The employment of advanced numerical analysis tools enables to understand better the pantograph-catenary interaction behaviour, supporting the design, development and de-risk the implementation of current collection systems. A challenging aspect to consider in these analyses is the contact wire height variation, e.g., found in level crossings and overbridges, and the associated vertical gradients that can impose train speed restrictions. To reach higher wire heights at level crossings, the pantograph has to extend from the train and its aerodynamic loads change, influencing the pantograph uplift forces. In this work a 3D multibody pantograph model is built and validated with experimental results. The aim is to analyse its interaction with a catenary with one level crossing and one overbridge. The aerodynamic drag and uplift forces applied on the pantograph components as function of its extension are computed in realistic operation scenarios using Computational Fluid Dynamics (CFD) approaches.