Simulation techniques are used to assess the dynamic interaction between overhead contact lines and pantographs, as part of the prediction of current collection quality. This document specifies functional requirements for the validation of such simulation methods to ensure confidence in, and mutual acceptance of the results of the simulations. This document deals with: - input and output parameters of the simulation; - comparison with line test measurements, and the characteristics of those line tests; - validation of pantograph models; - comparison between different simulation methods; - limits of application of validated methods to assessments of pantographs and overhead contact lines. This document applies to the current collection from an overhead contact line by pantographs mounted on railway vehicles. It does not apply to trolley bus systems.