Dangerous goods are considered to be those whose transport is only authorised in certain conditions, when a number of safety requirements or recommendations are in place. Here rail freight is regulated by the RID, the International Regulation on the Carriage of Dangerous Goods by Rail, issued by the European Union.
Among the goods considered dangerous for rail transport are explosive and flammable goods, gases and flammable liquids, and spontaneously combustible, toxic, infectious, corrosive and radioactive materials. The packaging and stowage of these kinds of substances in wagons or tanks must follow a series of additional procedures to guarantee the safety of both people and the environment.