This leaflet regulates the numbering of freight trains and engines running light in scheduled and spot European traffic which cross at least one border. It takes account of the needs of Railway Undertakings (RU) and authorised network users carrying freight traffic, as well as the needs of the Infrastructure Managers (IM). Application of the leaflet will ensure that international freight trains can be identified throughout the whole of their journey according to uniform principles and by purely numerical means. The numbering is valid for planned and operating trains.