This Technical Specification applies to apparatus, systems and fixed installations which are intended for use in the railway environment. The frequency range covered is 0 Hz to 300 GHz. Technical considerations and measurements are necessary for frequencies from d.c. to 20 kHz because no relevant field strengths are expected above due to the physical nature of EMF-sources in the railway environment. a) The regulations regarding the protection of human beings (also bearing active implantable medical devices) during exposure to non-ionizing electromagnetic fields in the railway environment are different according to the countries worldwide. The object of this Technical Specification is to summarize measurement and simulation/calculation procedures of magnetic field levels generated by electronic and electrical apparatus in the railway environment with respect to human exposure (also for human beings bearing active implantable medical devices). Transient conditions, such as short circuit, earth fault and transformer inrush are excluded. Not covered are personal electronic devices (e.g. mobile phones, notebook computers, wireless communication systems, etc.) of passengers and workers. Not covered are intentional transmitters with frequencies higher than 20 kHz.