When the wheels move along the rail, the rake tines travel along {HEAD ~ the openings} in {TAIL ~ the screen}, forcing any obstructing material into another portion of the material reduction apparatus 
in
When the wheels move along the rail , the rake tines travel along { HEAD ~ the openings } in { TAIL ~ the screen } , forcing any obstructing material into another portion of the material reduction apparatus
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH