This standard gives the rules for power resistors (for example, braking, heating, snubber and filter) used in the power and auxiliary circuits on board rolling stock irrespective of the circuit and the type of vehicle where they are used. These resistors are generally of open construction and are used in polluted areas. The construction consists of resistor elements of grids, plates, strips, ribbons or wires. This standard states - the characteristics of the resistors; - the service conditions with which the power resistors have to comply; - the tests intended for confirming that these conditions have been met and the methods to be adopted for these tests; - the information to be marked on, or given with, the resistors. This standard does not give requirements relating to general service conditions and general rules which are given in IEC 60077-1. The object of this standard is to adapt the general rules given in IEC 60077-1 to power resistors for rolling stock in order to obtain uniformity of requirements and tests throughout the corresponding range of components and to avoid the need for testing to tow different standards.