John Hagen has taken on the project of producing Tennessee Central Boxcar decals in HO scale. It will take him several months to get to this project as he has a backlog of work.
I have sent him all of the photos that I could find of these cars but I am sure that he would welcome more and if you also express interest maybe they will get bumped up on his schedule.
Here is what he said regarding costs:
"I am thinking I can get 4 per sheet with both the 50’s and 37 lettering. If so you’d be looking at $5.50/set or $20.00/4 sets"