Free movement of subsystems
Article 12
Without prejudice to the provisions of Chapter V, Member States shall not, in their territory and on grounds relating to this Directive, prohibit, restrict or hinder the construction, placing in service and operation of structural subsystems constituting the rail system which meet the essential requirements. In particular, they shall not require checks which have already been carried out: (a) as part of the procedure leading to the ‘EC’ declaration of verification; or (b) in other Member States, before or after the entry into force of this Directive, with a view to verifying compliance with identical requirements under identical operational conditions.