The rear pair of {TAIL ~ wheels} are coupled to the front pair of wheels through {HEAD ~ a drive assembly} 
The rear pair of { TAIL ~ wheels } are coupled to the front pair of wheels through { HEAD ~ a drive assembly }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD