This photo is from The Official Union Pacific Steam Club, on Facebook
This is a description from the photographer with a question. He states; “this was photographed a few days ago and it hasn’t been modified in any way.”
I also found the link provided by: Witz 41 very helpful • Another reference from www.steamlocomotive.com/types/tenders
Source: Union Pacific Railroad • Cheyenne, Wyoming
Gary: Rail-fan & Model Railroader