Upon {HEAD ~ arrival} at {TAIL ~ the desired location} and a given amount of time, the encapsulated breaker can be released 
at
Upon { HEAD ~ arrival } at { TAIL ~ the desired location } and a given amount of time , the encapsulated breaker can be released
OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH