I am repainting some Williams RDC cars as Jersey Central and would like to get as close to possible to the prototype. In a few pictures and videos the cars appear to be either grimy grey or black on top. Is that how they were painted or was this the result of the smoke output? I figure while I have these things stripped down I might as well get the paint or weathering correct. Anyone from Jersey Central territory know for certain?
A quick Google search produced a bunch of photos on the Wikipedia site, some of which had the black roofs, while others appeared to be all shiny stainless steel. Thus, it may depend on the era you are modeling, what the roof color should be.
On Railphotos there are two photos of CNJ RDC 551. The one taken in 1956 clearly indicates that, in that year, the roof was unpainted stainless steel. The one taken in 1975 looks like the roof of the end cap is black. It's an end shot and does not show the rest of the roof or the radiator hump, so it's impossible to tell whether it is from oily blow-by in the exhaust, or from black paint.