Ah! I get it now... the tram threw me for a few - after all, Philadelphia Zoo let theirs fall into disrepair *decades* ago - cost more to maintain than it made, I believe. But putting one in to not only view the zoo but to allow people to not have to walk up *that* hill... OK, that makes sense and might actually get enough use to be worthwhile - at least on the uphill side.

They're still working on their Elephant Walk area right now - but I don't remember seeing anything else animal-specific (and major) coming up after that, so general updating sounds like its time has come.