Hello Alexey,
I was not working on the sorting of stations.
Mainly, I was adding a second track with a second stop position at stations incl. the relations of the line. 

I do not see from Your list "Subway Validator", what is wrong or how I should map it differently.
Is it possible to link a OSM documentation page or something else, which shows precisive, what You mean with "unsorted stops" and "station and stop_positions not combined as stop_area relation"?
And what else is meant with "many errors"?
Thank You.
With regards,
Anna Catarina