Not sure how extensively you wanted to modify the AF steamers, but assume you weremay be interested in reducing the wheelset/driver flange depth and tread width. January, 1962 volume 2, No. 3 S Gauge Herald has an article on how to turn the AF wheelsets and the driver flanges to scale using a Dremel tool (available from Mobley Library from NASG; or, contact me off forum and I can copy one for you in PDF). The July 1968 issue of Model Railroader, Pg. 66+, MR Clinic has an explination of how to use a lathe to turn large flanged HO European manufactured wheelsets to a more prototypical profile.