10 years of fudging later, I have lived to tell the tale, lol. I have almost all the IHB and occasional lease units, plus some EJE, BRC, etc. for variety. I doubt the Atlas release of the new GP 38-2's actually ran in my time period, but I got them anyway. I know Gensets did run near the end of that time period.....but I don't like them so I doubt they will ever grace my representation of the IHB.
I also have a new layout, and it is subject to compression and rearrangement of the prototype. My main yard is now Michigan Ave yard, and the industries of oil, steel, mysterious heavy industry, chemicals, locomotive repair, and so forth all look pretty good to my eye.....they just aren't in the same order as the IHB sees them when leaving that yard. I have never really cared, figuring almost no one has that luxury. And, I have run the dead end line to another staging yard so I can have some through trains of sorts coming from the east, which I doubt happened as my track plan dictates.