What is the purpose of Zhan Tianyou's study in the United States?

Zhan Tianyou went to study in the United States as a public student of the Qing Dynasty. Under the guidance of American professors, Zhan Tianyou knew that he could join the United States as a skilled immigrant. After Zhan Tianyou studied hard and obtained American citizenship, Zhan Tianyou returned to China and began to build railways, thus rewriting the transportation calendar of modern China. But he didn't expect to be persecuted by corrupt officials of the Qing government, and the railway construction had to be handed over to the Qing government for profit. Zhan Tianyou returned to the United States in a rage and founded Hongbang.