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