Any railroad carrier subject to the provisions of 49 CFR 221, amended and revised through October 1, 1989, incorporated herein by reference, on file with the Office of the Secretary of State, and copies available from the United States Government Printing Office, P.O. Box 371975M, Pittsburgh, Pennsylvania 15250-7975, operating trains outside of yard limits without an occupied caboose at the rear of the train shall have an operable end-of-train device capable of activating the train's emergency air brake system electronically from the control panel of the locomotive controlling the train.
Ariz. Admin. Code § R14-5-114