Ankh-Morpork's Undertaking
I made an Undertaking (subway) map for Ankh-Morpork, set about 50 years in the future (from canon "now"). I took some liberties with names of places, given the time gap. For instance, Dolly Sisters has become Dollisters, the Whore Pits has become Harpits. Locations are based on the canonical Ankh-Morpork map. Note that the logo is actually octarine - your monitor may not be calibrated to display that color properly.
I used this map to help lay out the lines: