The zoo has a number of elephant husbandry models, this is one of them. The information was in Dutch (which I don't speak) so I can only guess that this is a crush, perhaps used to restrain the elephant for medical investigation?
@Ned
There would really be no use for a crush other than for 'medical' examination, in the broadest sense.
For those who don't know. a crush is often in the form of a transport crate for smaller animals, or a bespoke stall for larger ones. They are routinely used in Vet surgeries for pet animals and on farms and studs for agricultural animals. They form a means of physical restraint, holding the animal securely whilst it is attended for whatever reason. The sides and/or top often slide in towards the animal locking in place so close contact can be made safely. The animal may or may not be sedated during the process, depending on the circumstances. This model shows an advanced rotating crush (see the wheels, and circular frames at the ends) which would allow the animal to be restrained and tipped onto its side.