This International Standard specifies the general service conditions and requirements for all electric equipment installed in power circuits, auxiliary circuits, control and indicating circuits etc., on railway rolling stock. NOTE Certain of these rules can, after agreement between the user and the manufacturer, be used for electrical equipment installed on vehicles other than railway rolling stock,such as mine locomotives, trolley buses, etc. The purpose of this standard is to harmonize as far as practicable all rules and requirements of a general nature applicable to electric equipment for rolling stock. This is in order to obtain uniformity of requirements and tests throughout the corresponding range of equipment to avoid the need for testing to different standards. All requirements relating to: the environmental stresses expected during the normal service conditions; the construction; the performance and the associated tests which can be considered as general; have therefore been gathered in this standard together with specific subjects of wide interest and application, for example temperature rise, dielectric properties, etc. In the event of there being a variation of requirements between this standard and a relevant product standard, then the product standard requirements take precedence.