I also wanted to note that "international" is a bad category (Hannover
is a good example). Good that you already changed it, but I still think
the criteria are too much based on territories.
I think we should go more in that "dominance" direction, in particular,
we need to get rid of the "Bahnhofskategorie" thinking. This is a
categorization scheme that rather aims at a station's traveler
infrastructure, not its relative significance.
One example where your suggestion is too close to that Bahnhofskategorie
thinking: I don't see any difference between "suburban" and
except where they are. This is not important for the aim of this
Also, we'd need some way to differentiate Basel Bad Bf from Basel SBB,
Berlin/München Hbf from Ostbahnhof, København C from Nørreport. In each
of these examples, both mentioned stations have international traffic,
but one is definitly to be displayed at a lower zoom level than the other.
There's another problem that has not been mentioned yet: The scheme is
only aimed at railway networks, but we would want such a system for
underground networks, too, for example. And also for airports and bus
(Note that the importance of stations from different systems is not
strictly hierarchical: I would want to see an important underground
exchange station at a lower zoom level than some regional train stop;
and some important bus node earlier than a small underground stop.)
I'm thinking about a how to define a scheme that can cover all of this,
but I want to go to bed now, so I'll do that tomorrow, but already send
this mail to avoid people considering the discussion over ;)
 Yes, that lies outside the scope of openrailmap, but there's the
same problem when rendering a transit map, so we should develop a
solution that fits them all.