A quick and simple method to get rid of the plastic new freight car look is to spray a light coat of Dullcoat.  This will take away the 'toy' train look of your layout.  If you don't have any Testor's Dullcoat you can use any Matte Finish spray to get the same results.  Just a simple spray to each side and let dry.  This can be done to any plastic kits also.

Hopper Weathering Clinic II
By Bill Mock
December 2009

So here's how those BN Hoppers turned out after the surface rust dried. Not bad. I'll [ ... ]

Here is the deal. IF somebody wants me to make figures, they have to be SPECIFIC. If you dance around the subject and hint you want hookers,or anything [ ... ]