@Santa Fe Forbes, first, how did you come to respond to a SIX year old thread?
Would love to see photos of your train.
Six years ago--that's yesterday for me. A link to this thread was rendered by my searching the web for information related to The B&O's Columbian.
All of the posts herein related to production methods and "secret" manufacturing locations is interesting too.
In terms of The Columbian prototype-- I found it interesting that it was primarily an all coach Train (with one Sleeper added between Pittsburg and Chicago) running just "behind" The Capitol Limited.
I've yet to discover a good photograph of The Columbian being pulled by F3's. Generally, B&O Trains using F3's are pictured dragging mixed Freight.