Currently in Vienna, I saw quite a few SGP E2 types running all day on Monday to Fridays. They have not been seen running at the weekends. I saw them on line 1 and D (mixed with other types) though they do apparently also run on 2, 6, 11, 25, 26, 30, 38. Frustratingly, I only got a ride on just one example, not helped by not being able to track them (you can see at next departure displays if an arriving tram will be an SGP or not by whether it has a wheelchair sign on the display)
However I did ride a few examples of the SGP class 100 types on the Wiener Lokalbahn (or Baden Bahn). These are attached to low floor trams, and sometimes are the driving car (I assumed the older trams may just be attached rather than driven). Anyone visiting soon, the line is running in two sections (with a badly organised replacement bus in the middle). The SGPs were only observed running on the southern northern section between Quartier Belvedere and Inzersdorf.
The Ring Tram tourist line, using an older SGP E1, no longer appears to be operating.