This European-Standard is applicable to power electronic converters mounted on-board railway rolling-stock and intended for supplying: - traction circuits - auxiliary circuits of power vehicles, coaches and trailers The application of this standard extends as far as possible to all other traction vehicles, including trolleybuses for example. This standard covers the complete assembly together with its mouting arrangements containing - semiconductor device assemblies, - integrated cooling systems, - components of the intermediate d.c. link, including any necessary filters associated with the d.c. link, - semiconductor drive units (SDU) and related sensors, - incorporated protection circuits. The following types of power sources are taken into consideration: - a.c. contact lines, - d.c. contact lines, - on-board supplies such as generators, batteries and other electric power sources. This standard excludes converters which supply the electronic control and Semiconductor Drive Units (SDU). NOTE: Electronic control equipment of converters and those sensors not related to semiconductor drive units and the printed circuit board assemblies of drive units for power semiconductors (SDU) are covered by EN 50155. This standard defines terminology, service conditions, general characteristics and test methods of electronic power converters onboard of rolling stock.