Larry Smith wrote:
"The hopper car with some added parts is a very accurate model of a C&O car as well as the B&O car. There have been several articles on adding the parts to the C&O versions."
Here's one take on this upgrade:
The Athearn 40 ft offset quad is the ARA standard 70-ton quadruple hopper, with details closer B&O Class W-2 (non-peaked end, ladders vice grabs). It has not aged well - along with the usual issues with molded-on details and oversized sill steps and handbrake, the operating doors are especially overscale and toylike and the three brake components molded in one lump. It is the second of the two most ill-used models of all time (the first is the Athearn 40 ft steel boxcar), decorated in any hopper paint and lettering scheme and copied by many other manufacturers (Tyco, Rivarossi/Roco/AHM/Mehano, Cox/Bachmann) who offered even more bogus schemes. (There are actually quite a few legitimate paint schemes for these cars.)
This prototype has most recently been done by Broadway Limited and MTH and covered in Railway Prototype Cyclopedia Volumes 5 and 14.