Thanks MLW for explaining your technique on page 5 ( the "Rag Technique" ) . You mention that you use diluted Polly Scale paints.
Could you please list the name ( or the Polly Scale number ) of the colors you were using for the CN boxcars. I'm modelling the CN too.
Here goes another attempt. Not much merit on this one.
I used a fine mist of rubbing alcohol before applying some light weathering and a wash of acrylic paint diluted in same.