Sorry, wrong comment. Added grass ("rasengleis") for tram 23

Hello, Roland,
I am sitting at my desk within the ISD building as I am writing this, and I can assure you that it is correctly marked and that there is just an empty parking lot with some construction containers next to it (I can provide photo evidence, if you would like). The only possible addition that I would see fit is maybe to subtract the courtyard from the building.
Cheers,
Timon