What caused increasing numbers of people to join the populist party in the late 1900's?

The Farmers' Alliances agitated for railroad regulation, tax reform, and unlimited coinage of silver and attempted to influence the established political parties. Growth was so rapid, however, that interest in a third party began to increase; in 1891 delegates from farm and labor organizations met in Cincinnati. No decision was made to form a political party, but when the Republican and Democratic parties both straddled the currency question at the 1892 presidential conventions, a convention was held at Omaha, and the Populist party was formed (1892).