82It should be recalled that one of the objectives pursued by the charging system introduced by Directive 2001/14 is to ensure independence of management by the infrastructure manager. In other words, the latter must, as observed by the Advocate General at point 80 of his Opinion, use the charging system as a management tool. Thus, recital 12 in the preamble to that directive that states that charging and capacity-allocation schemes must encourage railway infrastructure managers to optimise use of their infrastructure within the framework set out by Member States. In order to make such optimisation possible, the managers must be granted some degree of flexibility, as mentioned in recital 20.