Philip,
I, unfortunately, don't have any photos to add that are not already on the internet. But, I have to state that I have been waiting a long time for someone to offer a good quality model of the SCL's bicentennial U36B #1776. That's personally a favorite of mine. I can't wait to see your progress, because I have never felt that the Bachmann model was even worth using as a start for a U36B kitbashing project. Prove me wrong.
I believe those Auto Train U36Bs were built to SCL's specs, because, if I recall correctly, they were placed on the tail end of an SCL order with GE. I forget the reason why, but that explains why Auto Train bought freight locomotives for its trains.
Back to our regularly scheduled programming,
Dave