A hydraulic motor is coupled to {HEAD ~ a front pair} of {TAIL ~ wheels} rotatably mounted to the front frame section 
of
A hydraulic motor is coupled to { HEAD ~ a front pair } of { TAIL ~ wheels } rotatably mounted to the front frame section
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH