Summary The International Union of Railways (UIC) was established on 20 October 1922 at the International Paris Conference. Its remit was to unify and improve the establishment of operating conditions for the railways in an international traffic perspective, i.e. as the rail transport standardisation body. Since that date, the UIC has kept on growing and now consists of 200 member bodies from almost a hundred countries from the five continents in many areas of competence. At the UN, UIC has observer status. UIC aims at developing international cooperation between rail enterprises and promoting worldwide the merits of international rail transport services. It maintains and develops the overall coherence of the rail system and implements engineering, operational and commercial interoperability requirements. UIC represents railway interests in lobbying and influencing decision-makers and the general public. The Community of European Railways (CER) was created in 1988 to represent the interests of the rail organisations of the EU countries as well as some other countries in Europe in dealings with the European Union's authorities. UIC Leaflet 471-3 provides a coherent approach applicable to all marshalling yards. In 2003 it was officially referenced as "best practices" in the Regulations concerning the International Carriage of Dangerous Goods by Rail (RID). The present version takes into account significant changes in rail legislation in the European Union to ensure coherence at European and a broader international level. In addition, the text outlining the context has been amended. Given past experience however, the bulk of the guidance document has not been amended.