A guide 1, {HEAD ~ wherein said housing} unfolds to facilitate {TAIL ~ installation} onto said track at any point along the length of said track 
unfolds to facilitate
A guide 1 , { HEAD ~ wherein said housing } unfolds to facilitate { TAIL ~ installation } onto said track at any point along the length of said track
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH