Hello,

metro/subway are never included in Interrail. 

Sometimes Suburban trains like S-Bahn in Germany are included.

About the local trains of the operator GW Train I don't know if they are included in Interrail.

While the trainplanner in the app may not be accurate for timings and the latest changes, I have never read any complaint that it wouldn't be accurate with respect to whether a train is included in the pass or not. 

So when filling in your journey I see that:

• IC-trains, without any intermediate stops, are included
• RE (regional) trains, with many intermediate stops, are not included 

This is likely to be due to different operators for the 2 types of trains but one would need to use another app (e.g. bahn.de) for that. 

Bahn.de says that the IC-trains are operated by Ceske Drahy (the national railways), while the RE-trains are operated by “GW Train Regio”. So this confirms what MartinM says.

If nothing changed then the GW trains are NOT included in Interrail!

There are certainly errors in this respect. Some of them have been corrected.