The Conference for Progressive Political Action was officially established by the convention call of the 16 major railway labor unions in the United States, represented by a committee of six: of the Machinists' Union, Martin F. Ryan of the , Warren S. Stone of the Locomotive Engineers, E. J. Manion or the , Timothy Healy of the Stationary Firemen, and L. E. Sheppard of the Order of Railway Conductors. The idea of joining the "forces of every progressive, liberal, and radical organization of the workers must be mobilized to repel these assaults and to advance the industrial and political power of the working class" seems to have originated with the National Executive Committee of the Socialist Party, which issued an appeal to unions and progressive political organizations for such a group