Transport of powder xerographic toners on a traveling electrostatic wave device is studied and numerical simulations are discussed relative to experimental results. Simple single particle descriptions, which have been the basis of previous theoretical work in the field, are contrasted to simulations which include many-particle interactions. Many-particle results are shown to exhibit self-consistent behavior essentially independent of the initial particle conditions. The average macroscopic velocity of the flow results from the interplay of the driving field and the interactions in the system. This velocity can take any value between zero and the wave phase velocity. This average velocity in the intermediate regime is achieved through the scattering of particles between different velocity states.