{HEAD ~ a carriage} affixed to said reflector and slidably mounted to {TAIL ~ said third rail} 
slidably mounted to
{ HEAD ~ a carriage } affixed to said reflector and slidably mounted to { TAIL ~ said third rail }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL