Rapido - PRR X31A Boxcars

My main weathering was to the roofs of these two Rapido models. The sides are kept clean looking.

Here is a view of my two Rapido PRR X31A boxcars. I purchased a single and double door boxcar awhile back. I found a couple of views with one being in color during 1952 which views these cars with weathered black roofs. I guess as the paint failed the black (primer or coating beneath?) is showing through. I decided to copy what I could see in this view.

It appeared there was some roof coating failure which resulted in a darker tone which I found neat to model. This was done using dollar store acrylic paints as a wash than overcoated with a brown shade of PanPastels. I think I used two tones for this coating. Each car was done a bit differently...George Dutka