{HEAD ~ The system} 17, wherein {TAIL ~ the section control system} is configured to communicate with a post control system over a wireless link 
wherein
{ HEAD ~ The system } 17 , wherein { TAIL ~ the section control system } is configured to communicate with a post control system over a wireless link
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH