I always thought that the phrase HC SVNT DRACONES (or Here Be Dragons for those of us who don't speak Latin) had traditionally been used on maps to denote the edge of the known world. It turns out that this isn't true. The only historical map to use the phrase is the Lenox Globe which dates to around 1510 and has the phrase inscribed near the eastern coast of Asia.
While lots of old maps did have sea serpents and other mythical creatures around the edge, the use of the phrase Here Be Dragons is quite recent. You can find a long list of modern cultural references on Wikipedia.
Sheffield isn't really the edge of the world (some people may dispute this) but I still think marking the train station with the words HC SVNT DRACONES would be allowed given this stonework above the entrance door.