**Offtopic: I even think about splitting the eursf highway system. I'm not sure about eurtr since there might be routes through more than one country. However, we already have nirtr and sctntr system, Australian tourist route systems are by region
nirtr, sctntr, Oz systems (and isn't there nortv?) are coherent things where those specific routes are treated as a coherent system. eurtr is a grab-bag for stuff that doesn't fit into those neat boxes. If the German routes, etc fit in their own defined system, then move them into a new system.
We also have the one (epic) route systems - chegts, irlwaw, dnkmr...
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Bringing it back to these airside people movers. There's one route in each of Canada, England, France, Italy, Spain, Switzerland and two in Germany. As there were issues about system proliferation, grab-bags is a sensible option for now.