To render Public Transport correctly is a tough one, especially since there are still a lot of tagging errors. It’s important that we user support PocketEarth in improving on this.
I took a quick look at your three examples. I do not really see what is your problem. Do you have the latest data update?
1) For Nussdorfer Strasse: I see only one stop (on the northbound track = Sibenhirten => Florisdorf) on OSM. But I don’t see the stop on the other track (Florisdorf => Siebenhirten) in OSM. But you tagged them both exactly the same way … strange. But on PE, both stops are there.
2) Währinger Strasse: dito on OSM, but correct on PE?
3) For Michelbeuern, I see two stops, one on each direction, which look absolut correct. (on PE and OSM)
Do you have any idea why 1) and 2) are not rendered on one track in OSM???
=> on the other hand, I see only one stop on “Jägerstrasse”, both on OSM and PE. => This seems due to the tagging railway=platform instead of railway=station. I corrected this one, let’s see if this will be corrected in PE after the next data update … (in OSM, I now see the station, at least on zoomlevel 17)