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
By Bill Mock
December 2009

Here is the first stages of weathering of my new BN [ ... ]

For the TL;DR - just scroll down an look at photos is useful since it's about architecture :) Feedback appreciated !

I want my layout to have a high level [ ... ]