Thanks Gregg,
It is not rocket science and it’s not particularly difficult…which is good or I wouldn’t be doing it…
If you are talking about the scrap piles / gondola loads:
1) I painted them with an airbrush… many times in fact until I got a rust colour I liked
( a mix of Tamiya Hull Red and Flat Yellow )
2) I gave the scrap a thin grime oil paint wash ( Dark Brown artist’s oil - like Van Dyck Brown with blue label Turpenoid as the thinner )
3) I used AK and Ammo rust pigments - 3 rust tones applied in different spots with a stiff brush…had some paper underneath to collect the pigments that fall off for

on other projects. Liberal application…just push it into the plastic, it’s easy..really
If you have a junk freight car, you can try the above routine to see how the products work for you…
Rome wasn’t built in a day and it took me a couple years to figure out what I was doing..eg my early IC hi-cubes vs Rock gon vs the NYDX hopper..weathering is as much as getting used to working with product rather than having an artistic talent and there is room for growth once you figure out what works for you…and what you like..
I haven’t posted much lately, as we had some home renovation and lately I have been doing cleanup on a basement flood… so really no time for the hobby right now…