Trainworx is your friend.
Beat me to that comment.
Also Athearn.
40ft trailers. You want lots of those. Maybe a couple Atlas 20 footers but not too many, or none at all because the Trainworx and Athearn are better models.
Trailer Trailer cars should be the brown/boxcar red. The yellow Trailer Train scheme debuted in 1970.
Can provide more detail on trailer schemes when I've a bit more time.
