location at which one of the switch actuating levers 18 19 engages a projection 25 28 29 the shaft 17 of the switch 16 is rotated through 90 degrees and the switch 16 is changed from one switch connection to the other immediately upon changing of the switch 16 the corresponding relay such as the relay 34 assuming that the cleaner 10 has been moving in a forward direction is deenergized interrupting the delivery of electric power to the tractor drive motor 12 and permitting the traveling cleaner 10 to coast to a standstill after a predetermined short time interval determined by the values of the circuit components of the circuit of fig6 the other relay 35 assuming that the change is from forward movement to reverse movement of the traveling cleaner 10 is energized applying electrical power to the tractor drive motor 12 in such a manner as to reverse its direction of rotation and reverse the direction of travel of the traveling cleaner 10 as will be understood the use of the trippable switch 16 together with the timing circuits as illustrated in fig6 differs from the previous practice in which the traveling cleaner was brought to a standstill by contact with an abutment at substantially the same time that the electrical power connections with the tractor drive motor were reversed by the abutment operated switch due to the tripping rotation of the switch levers 18 19 the traveling cleaner of this invention is able to overrun the projection location to such a distance as is appropriate for the 34 soft 34 stop start operation described in the drawings and specification there has been set forth a preferred embodiment.