Single-bay hopper plans?

Does anyone know where I can get plans for a steel, single-bay hopper? I’d like to scratch-build some for my narrow gauge layout.

Look for “ore car” or “ore jenny” plans. They are the only steel single hopper cars I know of. You can probably find plans for a EBT twin or triple steel hopper for 3 ft narrow gauge.Over the years I think MR, RMC and NG&SLG have all had plans for the EBT cars.