A limiting factor for the speed of a train is the capability of its current collection system. The current collection quality depends on the interaction between locomotive, pantograph and catenary. Limitations of the system are due to tunnels, bridges, section overlaps etc. The aim of this work is to get a better understanding of the dynamical behaviour of the current collection system with aspects on pantograph dynamics and critical catenary sections. This is done by a combination of modelling, simulation, analysis and experimental work. Critical sections found within the catenary system introduce an irregularity within the system that can lead to increased dynamic effects. The effect of critical sections are analysed through simulations and parameters that affects the dynamic response of the pantograph are studied. Problem arises when there is more than one pantograph on a train set. A finite element model of the system is used to analyse the interaction. Valuable conclusions on the dynamic and static characteristics of the system are taken and suggestions on improvements are proposed. Low elasticity variation as well as a level static pantograph height lowers the contact force variation, which thereby gives better current collection. An experimental set-up for a pantograph is designed and built with the ability to simulate both the vertical and horizontal excitation generated by the contact wire. Experiments are performed with the purpose to better understand the dynamic response and to study coupling effects within the pantograph. Measurements are performed for sinusoidal input signals both in horizontal and vertical directions representing the contact wire excitation. Periodic, sub-harmonic as well as irregular behaviour are shows to exist in the system. Differences in spring suspension characteristics and excitation is shows to introduce coupled motions. As a result of the work performed a better base is built on how to ease the operation with rnultiple pantographs. The results from experiments will be used to further develop the simulation tool used in this work.