The rail section further comprises {HEAD ~ an end portion} that defines {TAIL ~ one or more slots} that allow the one or more roller contact areas to deflect elastically relative to the body portion 
defines
The rail section further comprises { HEAD ~ an end portion } that defines { TAIL ~ one or more slots } that allow the one or more roller contact areas to deflect elastically relative to the body portion
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH