Abstract: A vehicle monitoring device includes a camera or other optical sensor configured to be disposed at a trailing end of a first vehicle system. The camera or other optical sensor is configured to output one or more images or video of a field of view behind the first vehicle system. The monitoring device also includes a controller configured to receive output from one or more sensors and to activate the camera or other optical sensor to output the one or more images or video based on the output from the one or more sensors. The output from the one or more sensors indicates one or more of a change in movement of the first vehicle system, a temperature, an acoustic sound, or movement of a second vehicle system.