A conveyor having selectively actuated rollers whose only external contact is with conveyed articles and a method for rotating such rollers. In one version, the rollers are driven by motors that are selectively energized by a wireless signal or a sensed conveyor position. In another version, the rollers are geared to a drive wheel that engages a bearing surface underlying the conveyor along the conveying path. The rollers are selectively actuated to push conveyed articles along the conveyor as it advances.