{HEAD ~ The insert} 52 is thus compressed within the cavity 50 and against {TAIL ~ the rail seat area} 18 of the tie 12 
{ HEAD ~ The insert } 52 is thus compressed within the cavity 50 and against { TAIL ~ the rail seat area } 18 of the tie 12
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH REL OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH