Abstract: An apparatus for determining the direction of travel of an electrically driven model train through a model railroad track layout having track segments with rails of opposite polarity is disclosed. A diode and transistor are operatively coupled to at least one rail of a powered track segment, such that passage of an electrically driven model train over the powered track segment in a first direction enables a flow of electrical current through the transistor to a signal or control circuit, while passage of the electrically driven model train over the powered track segment in a second direction does not. The polarity of the rails is determined by a circuit driven by a control circuit attached to an adjacent track segment.

Abstract: A press brake machine has a movable ram, a fixed bed, a drive for moving the ram toward and away from the bed, and a control system which controls movement of the ram. The control system includes an emitter which emits a beam of light and a detector assembly which detects an interruption of the light beam. The detector assembly includes two sensors and a beam splitter at which the light is directed. The sensors are connected in series such that if either or both of the sensors detect that the light beam is interrupted, a signal is sent to the drive to open the ram. The press is provided with a reset switch which is closed when the ram is moved to an open position. The reset switch is connected and operable such that the press brake cannot be reset if the light beam is interrupted.