In the closed position, the doors constitute side walls to prevent removal of {TAIL ~ the freight} from {HEAD ~ the vehicle} 
In the closed position , the doors constitute side walls to prevent removal of { TAIL ~ the freight } from { HEAD ~ the vehicle }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD