49 CFR 38.61 - Public information system.
(1) Requirements. Each vehicle shall be equipped with a public address system permitting transportation system personnel, or recorded or digitized human speech messages, to announce stations and provide other passenger information. Alternative systems or devices which provide equivalent access are also permitted. Each vehicle operating in stations having more than one line or route shall have an external public address system to permit transportation system personnel, or recorded or digitized human speech messages, to announce train, route, or line identification information.
(2) Exception. Where station announcement systems provide information on arriving trains, an external train speaker is not required.