A tensioning drive is provided at {HEAD ~ one end} of a section of {TAIL ~ the predetermined course} 
A tensioning drive is provided at { HEAD ~ one end } of a section of { TAIL ~ the predetermined course }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL