This document specifies the characteristics of the Passenger Alarm System (PAS) for Urban Rail. This document covers the PAS fitted to the passenger carrying Urban Rail rolling stock and specifies: the safety related requirements; the functional requirements of PAS triggered by pasasengers; the requirements for the communication channel between passengers and the driver or OCC; the requirements for the functional behaviour of the PAS; the requirements for the degraded modes management; the requirements for the Passenger Alarm Device (PAD) and PAD area. This document is applicable to the categories I to III of Urban Rail rolling stock defined in CEN/CLC Guide 26: (I) metros; (II) trams; (III) light rail. NOTE 1 CEN/CLC Guide 26 defines Metro, Tram and Light Rail as public transport systems permanently guided at least by one rail, intended for the operation of local, urban and suburban passenger services with self-propelled vehicles and operated either segregated or not from general road and pedestrian traffic. NOTE 2 The PAS function on existing vehicles may require modification to work in conjunction with vehicles that comply with this document. NOTE 3 This European Standard covers urban rail rolling stock, both with or without a driver. NOTE 4 For rolling stock devoted to suburban passenger services, this European Standard applies when the TSIs do not apply.