Weathering a CN N scale boxcar

[Herc Driver]

I like it! The blackened areas where the door would have slid and scuffed off paint looks good to me and sort of makes the whole car more convincing. Nice job!
The rust on the CP car in trail looks good too.

I've found some vey light yellow on that boxcar red towards the top looks pretty good too. Sort of gives a more sun-baked look.