This European Standard is intended to define the electromagnetic environment of the whole railway system including urban mass transit and light rail system. It describes the measurement method to verify the emissions, and gives the cartography values of the fields most frequently encountered. This European Standard specifies the emission limits of the whole railway system to the outside world. The emission parameters refer to the particular measuring points defined in Clause5. These emissions should be assumed to exist at all points in the vertical planes which are 10m from the centre lines of the outer electrified railway tracks, or 10m from the fence of the substations. Also, the zones above and below the railway system may be affected by electromagnetic emissions and particular cases need to be considered individually. These specific provisions need to be used in conjunction with the general provisions in EN50121‑1 . For existing railway lines, it is assumed that compliance with the emission requirements of EN50121‑3‑1 , EN50121‑3‑2 , EN50121‑4 and EN50121‑5 will ensure the compliance with the emission values given in this part. For newly built railway systems it is best practice to provide compliance to the emission limits given in this part of the standard (as defined in the EMC plan according to EN50121‑1 ).