Thanks for the replies so far. I just never know if what I post will be of interest.
The drivers are uninsulated; I did check, just in case. As I mentioned, I'm hoping to swap the 3rd rail shoes for a center rail roller type; I can't imagine that would be very difficult.
The more I tinker with this, the better it runs; that Lionel-looking reverse "disc" functions nicely, which is kinda cool.
Will continue to "putter" and post updates...
Mark in Oregon