Each car 14 comprises {TAIL ~ a hanger arm} 20 fixed to a carriage 22 supporting one or two grips 24, biased to {HEAD ~ the closed position} by springs 26 
Each car 14 comprises { TAIL ~ a hanger arm } 20 fixed to a carriage 22 supporting one or two grips 24 , biased to { HEAD ~ the closed position } by springs 26
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH