1.1 This Part 1 of the European standards series EN 50121 outlines the structure and the content of the whole set. This part alone is not sufficient to give presumption of conformity to the essential requirements 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 the induction effects of direct lightning strike. Emission limits at the railway boundary do not apply to intentional transmitters within the railway boundaries. Safety considerations are not covered by this set of standards. The biological effects of non-ionising radiation as well as apparatus for medical assistance, such as pacemakers, are not considered here. 1.2 This European Standard is supplemented by the following specific standards: EN 50121-2 Railway applications - Electromagnetic compatibility - Part 2: Emission of the whole railway system to the outside world EN 50121-3-1 Railway applications - Electromagnetic compatibility - Part 3-1: Rolling stock - Train and complete vehicle EN 50121-3-2 Railway applications - Electromagnetic compatibility - Part 3-2: Rolling stock - Apparatus EN 50121-4 Railway applications - Electromagnetic compatibility - Part 4: Emission and immunity of the signalling and telecommunications apparatus EN 50121-5 Railway applications - Electromagnetic compatibility - Part 5: Emission and immunity of fixed power supply installations and apparatus