I've wanted all four of these cars for a long time too.
You have to modify an Atlas car. Mine is just about done. I created a correctly sized cow decal. Modified the card ends.
I just need to place all of the louver details using decals from Archer, then add the ladder details and tackboards. Voila!
Paint, decal, and weather it.

Sidetracked with my wife right now though.
No RR stuff until she has recovered.
Best regards,
Michael