This Part 1 of the European standards series EN 50121 outlines the structure and the content ofthe whole set. This part alone is not sufficient to give presumption of conformity to the essentialrequirements of the EMC-Directive and must be used in conjunction with other parts of this standard.Annex A describes the characteristics of the railway system which affect electromagnetic compatibility(EMC) behaviour.Phenomena excluded from the set are Nuclear EM pulse, abnormal operating conditions and theinduction effects of direct lightning strike.Emission limits at the railway boundary do not apply to intentional transmitters within the railwayboundaries.Safety