Station ID signage looks like it's based on Tokyo Metro (compare this sign at Ginza line Nihombashi Station). For fun, Antarctica's Showa Station, listed as N-03 here, is a good 14000km/8750mi from Tokyo Metro's N-03 (Namboku line Shirokane-Takanawa Station).
Also, "Amund Line" (looks like a typo for アムン線/amun-sen) is of course a pun on Roald Amundsen.
