To improve the dynamic behaviour of a catenary system, the sections that limit the speed have to be found. A survey was made to gather information about critical sections of the catenary-pantograph system. Interviews with personnel at the Swedish National Rail Administration were performed and problem areas that need consideration were found and are presented. The purpose of this study was to find out how much of these critical sections affect the system and to suggest improvements to the design. Section overlaps and section insulators, both in combination with the usage of multiple pantographs, were modelled, and simulations have been performed at different speeds and for different catenary systems. As a result of this research, a better base could be built on how to ease the operation with multiple pantographs.