49 C.F.R. § 220.47 Emergency radio transmissions.
Title 49 - Transportation
An initial emergency radio transmission shall be preceded by the word “emergency,” repeated three times. An emergency transmission shall have priority over all other transmissions and the frequency or channel shall be kept clear of non-emergency traffic for the duration of the emergency communication.
Title 49: Transportation
PART 220—RAILROAD COMMUNICATIONS
Subpart B—Radio and Wireless Communication Procedures
§ 220.47 Emergency radio transmissions.
