The parameter of interference signals that determines the type of coupling is a frequency of interference signals. For the frequencies lower than 30 MHz, the conducted disturbances are dominant, however, for the higher frequencies, the signals transmitted by the electromagnetic field – radiated disturbances – becomes more and more important. The article presents the potential sources of interference occurring in the railway environment and discusses the methods of their elimination. The authors of the article carried out the measurements of conducted disturbances for two pieces of railway equipment – i.e. an information board and a DC/DC static converter. The paper includes the example results of normative measurements before and after the installation of a filter that eliminates the excessive levels of disturbances.