A method and apparatus for monitoring movement of a vehicle system. A sensor system monitors movement of a structure relative to a vehicle. The structure is connected to the vehicle in the vehicle system. A computer system identifies a number of distances from the sensor system to a number of objects associated with the structure. The computer system identifies an orientation of the structure relative to the vehicle using the number of distances from the sensor system associated with the vehicle to the number of objects. The computer system determines whether the orientation of the structure meets a number of criteria. The computer system initiates an operation for the vehicle system in response to an absence of a determination that the orientation meets the number of criteria.
