Wiener Stadtwerke work tram type KO no. 6133 (Simmering 1925, in service until 1986). This type of vehicle was used to transport ballast gravel, it has a tipping platform for this purpose. Coupled in front of two rail transport wagons st 7114 and 7115. Such a loaded rail train required two power cars, one on each end.

Wiener Straßenbahnmuseum, 2011-06-26.

tobias b köhler