In the 1916 through 1946 roster only the 2 "gondolas" are listed. However, this is kinda a rivet counter/ semantics thing. There are quite a few flat cars that were always on the roster as "flat cars", but had sides added for hauling hog fuel. The roster refers to them as flat cars converted to "crates". In the Otto Perry photos of the SVRy in the DPL collection these cars appear in most photos. There were for all intents and purposes high side gons. The hog fuel was hauled from Bates back to S.Baker to the power plant that used to set S. of the OLC mill and SVRy facilites. I don't recall seeing the cars that Taylor mentions that hauled the Chromium ore from Prarrie during the 1st WW, but adding stake pockets and sides to flats would be a cheap easy and reversible conversion.
The story on the Chromium ore I heard from Bob Bergstrom who found out about it from old newpaper articles in Prarrie City I believe. As I recall the story, the ore had high value during the war, but afterwards was nearly worthless, so the owner left a good amount unshipped on SVRy property. Eventually the rr assumed ownership of the ore for the storage fees against it. As it was already crushed, it became ballast.