There are a couple color versions of this sign that I am familiar with, the most common is blue, orange, and yellow. The one I have was made by and is marked Veribrite Signs-chicago-New York-Dallas.
This sign was unknown to me and is four colors, not three. The seller told me he removed it from a bldg. along an electric RR in Jackson MI., The RR ran from Detroit to Chicago. He also indicated that it may have been made in the Jackson MI State Prison, he worked in the prison and they had a sign shop making lots of different porcelain sign.
I am interested in others thoughts and especially any information about this sign.