Vienna, Austria.
Near Station Längenfeldgasse. U4 (U-Bahn) on the inner tracks, U6 (stadtbahn) on the outer tracks.
Bombardier Type Ts on the far left track and Type T1s on far right track. Siemens Type Vs are on the middle tracks.
U4 was also apart of the stadtbahn system, but it was gradually converted into a U-Bahn line from 1976 to 1981.
U4 during conversion (2mins 30secs):
https://www.youtube.com/watch?v=Nt7tg_LVlp0