This European Standard defines the acoustic requirements and the test requirements for warning horns, bells (single and recurring sound) and whistles for urban rail vehicles as defined in the CEN-CENELEC Guide 26, i.e. metro systems, trams, light rail, and 'local rail' systems. Additionally, the requirements for 'tram/trains' are included. NOTE The requirements for audible warning devices for mainline rail are found in prEN 15153 2.