I'm working on a map where the main theme is a railway line which runs vertically down the page. I've been wondering how to approach creating a scale bar for this map. To my eye a horizontal scale bar looks wrong in this case - it's not easily associated with the vertical content of the map, especially given that it's primary purpose would be to measure distances on the vertical railway line.
So I'm leaning toward a vertical scale bar, but I'm unable to find any literature regarding use of vertical scale bars, or even any examples of maps which utilise them.
Apart from the fact that no GIS packages capable of creating these out-of-the-box, is there any reason why using a vertical scale bar would not be appropriate?
Update: here's a quick mockup of a similar product to what I'm creating:
Update 2: more mockups based on @jbalk and @TDavis' ideas: