Armored trains of Poland mostly date to the World War I period. Many of them were modernized over the next two decades, and took part in most military conflicts of the Second Polish Republic, namely the Greater Poland Uprising, the Polish-Ukrainian War, the Polish-Bolshevik War, the Silesian Uprisings and the Polish September Campaign in World War II. Armored trains were also used by the Polish Armed Forces in the West as well as in the post-war period by the Polish Railroad Guards (Straż Ochrony Kolei) and the People's Army of Poland.