I've installed a few different packs for the HS Cylindrical hoppers.
The ones from GreatNortherner work fine (ATSF,CN, CP,GN) which I assume is because they're the dependency. The Alberta Heritage and Canadian Hopper pack show installed in the utilities, are listed as assets, and have geo's but the model will not display in the scenario editor.
I think I may also have the same problem with the GX Def cars but I haven't dug into it yet.