Described herein are self-propel accessories for walk behind/push-drivenmachines/devices comprising: drive assembly motor(s) operatively connected toat leastone power supply； at least one drive assembly for imparting drive from thedrive assemblymotor(s) to at least one accessory wheel assembly that is operativelyconnected to an outputshaft of the drive assembly motor(s) and one of an axle or a drive engagementsurface ofthe at least one accessory wheel assembly having accessory ground engagementwheel(s)coupled to at least one end of the axle for rotation therewith； a controllerfor the driveassembly motor(s) having an actuator for engaging the drive assembly motor(s)；and anattachment assembly for coupling the drive assembly motor(s), the at least onedriveassembly and the at least one accessory wheel assembly to a housing of thepush-drivenmachine or device in place of a wheel assembly/sub-assembly of the push-drivenmachineor device.
