David Payne asked:
"Does anyone have a list of owners of the subject hopper car; specifically, one with flat ends (for all I know, they may all have had flat ends)."
Anthony Wagner replied:
"Off the top of my head circa 1950: RDG, CNJ, D&H, LV, WM, and N&W. AFIK only the N&W cars had peaked ends. In later years some of these cars moved to other RRs secondhand."
Be advised that not all of these cars are the same dimensionally, with 29 ft and 30 ft 6 in inside length variations. Additionally, the Western Maryland built larger capacity versions of these cars in the late 1950s. Don't assume the Stewart/Bowser model will cover all of these cars - there's still a use for the Ulrich model and a need to scratchbuild or find an old RailRoad Progress scratchbuild in a box for the later WM cars.