The trailer can be tilted backwards until {HEAD ~ a back end} of the trailer contacts {TAIL ~ the ground} so that cargo can be easily loaded into the trailer 
contacts
The trailer can be tilted backwards until { HEAD ~ a back end } of the trailer contacts { TAIL ~ the ground } so that cargo can be easily loaded into the trailer
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH