 The SKB-2 heavy tank design bureau in Chelyabinsk started the KV-13 program, which two years later resulted in a line of successful Iosif Stalin heavy tanks.The Uralvagonzavod complex in Nizhny Tagil developed the T-43 medium tank.Uralvagonzavod included the Morozov Design Bureau, the designers of T-34, who were able to draw on its previous work on the advanced T-34M project.