In service, when used in connection with passenger equipment, means:
(1) Passenger equipment subject to this part that is in passenger or revenue service in the United States; and
(2) All other passenger equipment subject to this part in the United States, unless the passenger equipment:
(i) Is being handled in accordance with §§ 238.15, 238.17, 238.305(d), or 238.503(f), as applicable;
(ii) Is in a repair shop or on a repair track;
(iii) Is on a storage track and is not carrying passengers; or
(iv) Has been delivered in interchange but has not been accepted by the receiving railroad.