IEC 60077-1:2017 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. The purpose of this document is to harmonize as far as practicable all rules and requirements of a general nature applicable to electric equipment for rolling stock. This new edition includes the following main technical changes with regard to the previous edition: descriptions regarding insulation coordination, environmental conditions and those of current return and protective bonding are deleted and replaced by references to IEC 62497a??1, IECA 62498-1 and IECA 61991; classification of equipment type is introduced; temperature limits and temperature rise tests are reviewed.