Starting in 1996, Wm. K. Walthers began the introduction of a series of H0-Scale steel mill plastic assembly kits. This significant product line has done a great deal to spur the modeling of steel mills. Years later, some of these same kits were also manufactured in N-Scale.
One important aspect of the Walthers kits is that they were described as “Plastruct-friendly”, which is to say that many of the dimensional pieces such as girders and pipes were the same dimension as comparable plastic pieces manufactured by Plastruct. This is especially helpful for expanding the kits into bigger models. In particular, the “high line” of the blast furnace is not nearly as large as what is found on the prototypes. Using additional Plastruct pieces, you can expand the high line into a much more realistic model.
Walthers published a steel mill book by Dean Freytag at the beginning of the manufacturing cycle for the steel mill kits. It is now out of print, but turns up with regularity on eBay. Likewise, Plastruct has also published another Freytag book, “The Cyclopedia of Industrial Modeling”, which is still in print.
In this section, there is one page devoted to construction issues found with these kits. In particular, the Peach Creek Shops site has extensive information concerning the construction of a realistic model of a steel mill. Likewise, the Kalmbach book titled “The Model Railroader's Guide to Steel Mills” by Bernard Kempinski is very helpful Please see, here.
Also, Yahoo Groups has at least two steel mill modeling discussion groups which may also be a source for information about these kits.