The prototype of these cars was built by the Greenville Steel Car Company for the Southern Railway from 6-7/1980 (Series 134500-134649) (HS-51) and 7-8/1981 (Series 134650-134749) (HS-52) This HO Scale 1:87 Greenville 100-Ton HS 51/HS 52 Woodchip Hopper Pack STL files comes with the bodies of the HS-51 and HS-52 woodchip hoppers, 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!!!