This document specifies the common requirements and definitions for all power converter applications in fixed installations for power supply of railway systems. This document applies to fixed installations of following electric traction systems: " railway networks, " metropolitan transport networks including metros, tramways, trolleybuses and fully automated transport systems, magnetic levitated transport systems, electric road systems. This document applies to AC/DC converters, DC converters and AC converters. Converters for improvement of power quality and for energy saving are also included. Converters connected to electric traction systems feeding 3AC, 1AC or DC systems for auxiliary purpose are not in the scope of this document but some aspects such as insulation coordination and railway specific conditions may be referred to.