I've seen CSX locos in grey and blue. Why the difference? You're not going to tell me ones Union and the other Confederate, eh?
I remember hearing back during the Civil War B&O/C&O had some of their engines in grey and yellow and some in blue and yellow for just that reason. Some of their trains had to go through Confederate territory and some through Union territory so they needed to use them in order to not be seen as supporting the enemy of either side.
