The Populist Party (its real name was the "People's Party") responded to the conditions of the Gilded Age by trying to increase the power of farmers and, to some extent, workers. They also tried to decrease the power of the rich.
One of the major ways the Populists tried to do this was through government ownership of major utilities and through regulation. The Populists tried to get the government, for example, to regulate the prices railroads could charge for hauling freight. They also tried to get the government to take ownership of things like electric and telephone systems.
In these ways, the Populists hoped, the power of the rich would be decreased and the farmers and workers would have more power and better lives.