Circus/Zoo history

The caption with the above photo reads: "Zirkus-Rentner im Zoo: Elefantendame Nana war stolze 58 Jahre alt, als sie Ende der 1950er Jahre vom Zirkus Krone in den Kölner Zoo umzog. Sie reiste mit der Bahn an und ging die letzten Meter zu Fuß."

From what I can understand untell someone is kind enough to translate is, this is a picture of Circus Krone taking an elephant named Nana who was 58, to the Cologne zoo where she was retired. Interesting to me is that I believe that is Carl Sembach in the trench coat with the pipe in front. The elephant on the off side appears to have a leg chain on, and appears to be pulled by the truck in front of her. The man on the right side of the elephant(instead of the left) would probably the show trainer, and the man walking beside him looks like he has on a zoo uniform, and is probably from the zoo. What do pictures really tell us? Was the elephant retired because she was old and should no longer have to perform? Or was she a tough elephant, and possibly a runner, given that she is hobbled to a truck. Is that why there is another elephant there? To keep her company, as she was herd bound and didn't want to leave the herd? Or was the other elephant there as a block between Nana? Was the other elephant a Cologne zoo elephant coming to escort Nana the last steps as there is a zoo keeper apparently friendly with her? If it is a Cologne zoo elephant, why is the circus trainer obviously controling her, and not the zoo keeper? A lot of question's are raised in old photo's and not many answer's. What do you readers of the the blog think this picture "says?"