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