This European Standard outlines emission and immunity requirements for all categories of rolling stock, encompassing traction stock, hauled stock, and trainsets, including urban vehicles used on city streets. It specifies emission limits for rolling stock towards the external environment, ending at the interface with their respective power inputs and outputs. For locomotives, trainsets, and trams, this interface is typically the current collector (pantograph, shoe gear), while for hauled stock, it is the AC or DC auxiliary power connector. Although the current collector is part of traction stock, efforts are made through the slow-moving test to mitigate its influence. Additional compatibility requirements within the railway system may be identified in the EMC plan (e.g., per EN 50238). All equipment integrated into a vehicle must comply with EN 50121-3-2 standards. In exceptional cases where full compliance with EN 50121-3-2 is not demonstrated but meets another EMC standard, integration measures or specific EMC analysis and testing justify deviations. Electromagnetic interference concerning the entire railway system is addressed in EN 50121-2, with these provisions intended to complement those in EN 50121-1. The frequency range considered spans from 0 Hz (DC) to 400 GHz, with no measurements required at frequencies where no specific requirement is stipulated.