Aerodynamic effects on pantographs and overhead wire systems

Abstract This chapter considers the aerodynamic behaviour of pantographs and overhead line systems. After an introduction to the geometry of such systems, the mechanical and aerodynamic forces on the overhead wire are set out. The static and dynamic displacement of the wire due to wind effects is described. Wire instabilities caused by galloping are then discussed at length and the circumstances under which these instabilities might occur are derived. The different types of pantograph are then discussed and the types of mechanical and aerodynamic forces experienced by pantographs are outlined. Full-scale measurements, wind tunnel measurements and CFD calculations of pantograph aerodynamic characteristics are considered. The important issue of pantograph aerodynamic optimisation is then discussed at length for both lift forces and drag forces. Finally, methods are described for analysing the dewirement problem and for predicting the risk of such incidents.