Perhaps the Lionel team should make the Johnstown America or Freight Car America or Trinity version of the Five-Bay, Open-Top, aluminum-body hoppers with rotary couplers next time.
Those have not been produced in O scale.
These aluminum open-top hoppers were in a BNSF freight train moving over the CN/GTW line in Michigan on March 27th, 2019. All of the rotary coupler gondolas and hoppers can be mixed together.
Andrew