Here is a picture of a double deck FGEX reefer with very prominent DO NOT HUMP placards and its placed behind the UP F-3 diesels.

https://donstrack.smugmug.com/UtahRails/Emil-Albrecht-Photos/1948-Jan-Salt-Lake-City/i-WJhZ5dt/A 

Why would a refrigerator be so placarded?  Likely hauling eggs?  I have not seen many such placarded reefers.

Gary Laakso

south of Mike Brock