must be registered with the Intergovernmental Organisation for International Carriage by Rail (OTIF) and the European Union Agency for Railways (ERA) and which is unique throughout Europe and parts of Asia and Northern Africa. The VKM must be between two and five letters in length and can use any of the 26 letters of the Latin alphabet. Diacritical marks may also be used, but they are ignored in data processing (for example, Ö is treated as though it is O). The VKM is preceded by the code for the country (according to the alphabetical coding system described in Appendix 4 to the 1949 convention and Article 45(4) of the 1968 convention on road traffic), where the vehicle is registered and a hyphen. Some examples: When a vehicle is sold it will not normally be transferred to another register. The Czech railways bought large numbers of coaches from ÖBB. The number remained the same but the VKM changed from A-ÖBB to A-ČD. Europe 1964 to 2005 The UIC introduced a uniform numbering system for their members based on a 12-digit number, largely known as UIC number. The third and fourth digit of the number indicated the owner, or more precisely the keeper of the vehicle. Thus each UIC member got a two-digit owner code. With the introduction of national vehicle registers this code became a country code. Some vehicles had to be renumbered as a consequence. The Swiss company BLS Lötschbergbahn had the owner code 63. When their vehicles were registered, they got numbers with the country code 85 for Switzerland and the VKM BLS. Example for an "Einheitswagen" delivered in 1957: delivered as BLS B 831 renumbered with UIC number 50 63 20-33 801-5 rebuilt 1991 and renumbered 50 63 20-33 705-4 registered as 50 85 20-35 451-7 CH-BLS United Kingdom In the United Kingdom, prior to nationalisation, wagons owned by the major railways were marked with codes of two to four letters, these codes normally being the initials of the railway concerned; for example, wagons of the Great Western Railway were marked "G W"; those of the London, Midland and Scottish Railway were marked "L M S", etc. The codes were agreed between the railways and registered with the Railway Clearing House. India In India, wagons owned by the Indian Railways are marked with codes of two to four letters, these codes normally being the initials of the railway