49 CFR § 220.305
Use of personal electronic devices
November 18, 2020
A railroad operating employee must have each personal electronic device turned off with any earpiece removed from the ear—
(a) When on a moving train;
(b) When any member of the crew is—
(1) On the ground, or
(2) Riding rolling equipment during a switching operation; or
(c) When any railroad employee is assisting in preparation of the train for movement.