Iread an article from time. com saying that reconstruction did not fail, but it was overthrown. what do they mean by "overthrown"?

The Times Magazine article that you mention in the question says that Reconstruction was overthrown because the reforms and measures put in place after the civil war were actually working and in many cities, black communities began to prosper. It took active discrimination and enfringement on the rights of African American citizens to undo the gains that had been made and so in this sense Reconstruction did not fail, it was "overthrown."  

Explanation:

The Times Magazine article mentioned in the question summarizes the research of historian Allen C. Guelzo who says that it is incorrect to think that the Reconstruction failed. The Reconstruction was largely unsuccessful because it was not able to implement the gains that had been made due to 6 factors. The Times Magazine articles says the 6 factors are: 1) the inexperience of officials who were expected to lead the political reconstruction of a large part of the American territory; 2) the presence of insurgents who resisted the Union in the South; 3) the lack of military response to the insurgency; 4) the loss of the Radical Republican politicians who incentivized the issues that led to the civil war; 5) the Northern Democrats regaining power and withholding their support for reforms; 6) and questionable decisions taken on the part of the federal courts which exemplified shortsighted views of the efforts at political and social change that were underway.

i would think it's industries and hydroelectric power