More generally if you try to do the whole world in one go you are not going to reach useful quality because every place has something unique about it in the transit network itself and also the map is curated by different people who do things differently. The map might look similar to an outsider but the particular codes, conventions and methods will be different.

The answer for this, I think, is that either the OSM data (input) needs to adapt to fit what this system can read or patch rules and patch data can be applied to fix up the output.

Either way it is a distributed project, people in Tokyo or Hannover or any place where it is wrong are the people who would know what is right so they should be engaged in the solution.