17. In this Schedule—
(a)“audit” means systematic assessment of the adequacy of the management system to achieve the purpose referred to in paragraph 5(d) carried out by persons who are sufficiently independent of the system (but who may be employed by the duty holder) to ensure that such assessment is objective;
(b)“management system” means the organisation and arrangements established by the duty holder for managing his undertaking;
(c)any reference to an operation undertaken by a duty holder is—
(i)where the safety case is prepared pursuant to these Regulations by an infrastructure controller, a reference to the operations he carries out in relation to the railway infrastructure concerned; and
(ii)where the safety case is prepared pursuant to these Regulations by a person who operates trains or a station, a reference to the train or station operations concerned; and
(d)any reference to operations undertaken includes operations which are intended to be undertaken.