Start Level 1 Node: Trailers and CompartmentsTrailers and CompartmentsEnd Level 1 Node: Trailers and Compartments
   Start Level 2 Node: TrailerTrailerEnd Level 2 Node: Trailer
   Start Level 2 Node: CompartmentCompartmentEnd Level 2 Node: Compartment
      Start Level 3 Node: Examples of CompartmentsExamples of CompartmentsEnd Level 3 Node: Examples of Compartments