Great post! The ingenuity of your system is quite impressive as is the workmanship. A Williams scale GG1 will operate on as little as 0-42 curves so you may consider getting road number 4935 and installing DCC in it. With replaced pantographs, it would be a much better model. 4935 in PRR DGLE was among the last of the GG1s to operate for Amtrak and saw some service for New Jersey transit in 1982 on lease after Amtrak stopped running theirs.
Off course the choice to avoid the GG1 based on your modeling period is completely understandable. I have an Atlas AEM7 and a NJT ALP44 and they are both wonderful models even if my AEM7 needs a run through the Wilmington Shops for a major overhaul.
With your modeling skills, you could do justice to a new 3D printed O scale E60. I don't remember the site, but there are available for $85.00 and are designed to run on a MTH U30C chassis. Lot of prep and assembly is required, but with your skills it wouldn't be a difficult project.
