Those modelling the more modern era, and who need an easy-to-build industry for covered hoppers, can find a great prototype to model just off Hwy. 401 in Mississagua, Ontario: Three tracks, and sometimes 5-6 (or more) hoppers lined up at the same time.
Thanks for providing the idea. As you have mentioned industries such as you have suggested provide an opportunity to have some switching interest without having to do a lot of detail work in setting up the site. There are plenty of opportunities out there - we just have to look.
Is just a siding truck parking area and portable car unloader, or pipe work heading off the edge of the known world could be any covered hopper carrying any suitable product.