Passing a train the other day I was stunned by a range of iconographic metadata printed on the side of a carriage (click on image for full picture). Clearly these were not there by chance or artistic intentions, but meant something to someone (although most looked pretty strange to me). It seem to include info about e.g. the home station of the carriage (or maybe where it was built), or electrical information. Anyway, a good example of metadata for specialists – not intended for the general public.