{HEAD ~ A number} of {TAIL ~ runs} of completed insulating glass components in queue to be assembled into insulating glass units at the assembly station is monitored to identify a low queue condition of a given type of insulating glass component 
of
{ HEAD ~ A number } of { TAIL ~ runs } of completed insulating glass components in queue to be assembled into insulating glass units at the assembly station is monitored to identify a low queue condition of a given type of insulating glass component
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH