Well file this under “wish I’d thought of that”. This amazing set of post cards from Drawn By Day, a UK based designer, takes the track maps of the various London Underground subway depots and gives them the old Harry Beck treatment.
In order for it to be recognisable as related to the Tube map, each road, as they’re known, is drawn either vertically, horizontally or at 45º. You’ll notice that on the Tube map, the only places where two lines cross each other at 90º are where there is an interchange — and since there are no interchanges in a depot, all the roads which intersect are at 45º to each other. I also kept the orientation of the depot as closely as possible; if the depot runs north to south, it runs top to bottom on a portrait postcard.