The prototype of the car was built by the National Steel Car Company for the Union Pacific (Series 94100-94449), Chicago, St Paul, Minneapolis & Omaha/Union Pacific (Series 366900-396579) and Granite Mountain Quarry (Series 1-105) This HO Scale 1:87 NSC 2500 Cubic Foot Aggregate Gondola STL files comes with the body phase I, II and III, brake wheel and coupler box covers. The only thing that you need to complete this model is some 100-ton rolling bearing trucks with 36' metal wheels and metal couplers of your choice. Also you need 2-56 x 1/4 phillips pan head screws for the trucks and 2-56 x 1/8 phillips pan head screws for the coupler boxes. Note these STL files is for personal use only and not to be commercially reproduced!!!