What is of particular importance in view of the development and operation of fast railway transport is the overhead system vibration excited by pantograph motion. The problems discussed in the paper are related to continuous system vibration under moving loads. Modelling the catenary-pantograph system is connected with motion of two subsystems, namely: continuous (contact wire) and discrete (pantograph). In the paper, the results of research on dynamical phenomena caused by the interaction between the pantograph and catenary are presented. The stiffness of the catenary wire is taken into account. The dynamical phenomena occurring in the system are described by a set of partial and ordinary differential equations. The solution to these equations has been obtained using approximate numerical methods.