{HEAD ~ The chain guide} 50 is secured by {TAIL ~ a support} 52 to the rail 40 
is secured by
{ HEAD ~ The chain guide } 50 is secured by { TAIL ~ a support } 52 to the rail 40
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH