@James E
The whole project for the new Hauptbahnhof affected (and still affects because not completed yet) an area of more than 1 sqkm (100+ hectares, approx. 250+ acres).
Starting in 2009 every building on that space was taken down, including some apartment buildings whose inhabitants had been "convinced" to move out, something rather rare in Vienna.
Then the new central train station was built, including the underground BahnhofCity shopping mall. Northeast of the train station Quartier Belvedere emerged, a large business complex. Southeast the Sonnwendviertel was created with more than 5000 new apartments including required infrastructure (schools, doctors, shopping, tram, park, etc.). The planned connection to the Autobahn (freeway) is still not complete, though. (Some buildings belonging to the Austrian Army are in the way, but demolition has started eventually.)
These activities also ameliorated adjacent areas, most notably along Sonnwendgasse. (Nevertheless Emily is always warning of this area.)
So the 10th city borough, said to be a low-income and blue-collar worker area, has got an uptick in quality.
The downside is rising costs for renting (or buying) an apartment. Apartment prices rise up to four times the yearly inflation, a problem the City of Vienna tries to get under control, but with no avail. Consequently a different clientele will move into this area who can afford this.