Circa 1928-29 - It's the same color as the 1928 Greenway set, but we're assuming this was used as an early version of the 1929 set that was cataloged as the Dixie Flyer. Ives called it emerald green in the 1929 catalog.

In 1929 the 3257 was cataloged with only one set and came in the light green seen above. Note that this locomotive has nickel trim. Below is the same engine with brass trim. 

In 1930 the 3257 was changed back to orange, although a somewhat darker orange than 1928. It came in sets with the 141-142 passenger cars also in orange with black roofs.