National Rail is a title used by the Association of Train Operating Companies (ATOC) as a generic term to define the passenger rail services operated in Great Britain (before the adoption of the term National Rail, "Great Britain Passenger Railway" was used). ATOC is an unincorporated association whose membership consists of the passenger train companies of Great Britain which now run the passenger services previously provided by the British Railways Board (from 1965 the Board used the title British Rail). National Rail generally does not include services that do not have a BR background; this distinction is important because National Rail services share a ticketing structure and inter-availability that do not necessarily extend to other services.