A 3D printable Ortner Rapid Discharge 3 Bay Aggregate Hopper in HO 1/87 scale, O 1/48 scale, and N 1/160. In HO and O, two versions are included, one with molded on grab irons and one for separately applied wire grab irons. In N, just molded on grab irons are included. Also two variations of internal bracing are included in all scales. In HO, use 33 inch wheels, otherwise the coupler will be too high without shimming.