Section 299.419 - Emergency communication(a)PA (public address) system. Each passenger car shall be equipped with a PA system that provides a means for a trainset crewmember to communicate by voice to passengers of his or her trainset in an emergency situation. The PA system shall also provide a means for a trainset crewmember to communicate by voice in an emergency situation to persons in the immediate vicinity of his or her trainset (e.g., persons on the station platform). The PA system may be part of the same system as the intercom system.(b)Intercom system. Each passenger car shall be equipped with an intercom system that provides a means for passengers and crewmembers to communicate by voice with each other in an emergency situation. Except as further specified, at least one intercom that is accessible to passengers without using a tool or other implement shall be located in each end (half) of each car.(c)Marking and instructions. The following requirements apply to all units of a trainset:(1) The location of each intercom intended for passenger use shall be conspicuously marked with HPPL material in accordance with § 299.423 ; and(2) Legible and understandable operating instructions shall be made of HPPL material in accordance with § 299.423 and posted at or near each such intercom.(d)Back-up power. PA and intercom systems shall have a back-up power system capable of- (1) Powering each system to allow intermittent emergency communication for a minimum period of 90 minutes. Intermittent communication shall be considered equivalent to continuous communication during the last 15 minutes of the 90-minute minimum period; and(2) Operating in all equipment orientations within 90 degrees of vertical.(e)Additional requirements. The PA and intercom systems shall be designed to operate without failure and remain attached under the conditions typically found in passenger rail equipment including expected mechanical vibrations, and shock in accordance with § 299.405(a)(1) , as well as comply with electromagnetic interference criteria in § 299.435(e) .