A pair of elongated connector pipes {HEAD ~ each} having one end portion connected to the support structure for {TAIL ~ movement} along the track 
A pair of elongated connector pipes { HEAD ~ each } having one end portion connected to the support structure for { TAIL ~ movement } along the track
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH