I just finished reading it through today, and I've got to say, I am thoroughly impressed.
All the is were dotted and the ts were crossed. I now understand a LOT more about the steel making process, and how RRs work with it.
The only thing I would've liked would've been more coverage on the steel mill periphery industries. I feel that a fully integrated, merchant, or even mini-mill is one of those things that far too complex to find a good home on most layouts, however, the peripheral industries (by-product sales, etc...) sound like they'd be IDEAL layout industry candidates, and I'd love to learn more about THOSE.