This part of IEC 62236 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 document specifies the emission limits of the whole railway system to the outside world. The emission parameters refer to the particular measuring points defined in Clause 5. These emissions are assumed to exist at all points in the vertical planes which are 10 m from the centre lines of the outer electrified railway tracks, or 10 m from the fence of the substations. Also, the zones above and below the railway system may be affected by electromagnetic emissions and particular cases are considered individually. These specific provisions are used in conjunction with the general provisions in IEC 62236-1. For existing railway lines, it is assumed that compliance with the emission requirements of IEC 62236-3-1, IEC 62236-3-2, IEC 62236-4 and IEC 62236-5 will ensure the compliance with the emission values given in this document. For newly built railway systems, it is best practice to provide compliance to the emission limits given in this document (to be defined in the EMC plan according to IEC 62236-1).