The various Car Builder's Cyclopedias (or Car and Locomotive Builder's Cyclopedias) would also be useful to you. The MR digital archives have lots of drawings of freight cars but I suspect it would be a laborious task to seek out only the AC&F cars unless those letters or words were part of the title for the drawing.
Dave Nelson
MR has its all-time digital archive, which will index those in some fashion. They're offering a free 24 hour trial access in return for signing up for the newsletter, so you can give it a try:
http://mrr.trains.com/archiveaccess
Mike Lehman
Urbana, IL
If you are a member of the NMRA, you can access the digital archives.
Phil, CEO, Eastern Sierra Pacific Railroad. We know where you are going, before you do!
Does MRR have a collection of digital drawings that we can search or sort on? I'm looking for information about ACF freights cars - some from early 1900 era and 1960-70 era.