Abstract: A robot for cleaning a floor of a railroad vehicle has a robot body equipped with a cleaning mechanism and includes a travel mechanism controllable for locomotion in a desired direction. The robot also includes a distance detecting arrangement directed at least toward the front and opposite sides of the robot body for measuring the distance to an obstacle or a wall, and a map storing arrangement which has stored therein a cleaning region of the floor previously as a two-dimensional map. The robot also includes a path storing arrangement which has stored therein a predetermined path of travel for cleaning the floor as expressed in coordinates on the map. A first control arrangement is provided for recognizing the coordinates of the position of the robot body on the map based on outputs from the distance detecting arrangement when the robot body is placed at an end portion of the floor.