E 4417 ran from the beginning of 1961 until the end of 2000 and will be about half-way through its life at the time of this photo, taken at Südbahnhof.

The destination is unusual and seems to relate to a fairly short-lived extension of the O service beyond Praterstern to Elderschplatz along track which was last served by the 21 tram until it was replaced by the U2 in 2008.

Photograph by courtesy of Phil Sposito