In a previous post (here) I offered an opinion that while steam locomotives can be all shades of black, "Grimy Black" - actually a dark gray - is not one of them.
I got several email replies to that post claiming that the "shiny" engines were from an earlier era - by the late steam era the locomotives were allowed to get dirty and turn "Grimy Black" in color. Another claimed that since the engine I offered as an example was a passenger locomotive (4-8-2 no. 600) she would have been better maintained.
Such would not be true of, say a workaday 2-8-0 on a way freight.
Here's a shot of M-3-a 2-8-0 no. 454 working the Southern Division local. This was taken in the fall of 1956 - and 454, and all other CV steamers, would be retired within a few months. Hardly something that would be pulling the pride of the line…and again she's weathered but certainly not Grimy Black.