a) a door mounted on a frame for {HEAD ~ lateral movement} on tracks between a first open position and {TAIL ~ a second closed position} 
a ) a door mounted on a frame for { HEAD ~ lateral movement } on tracks between a first open position and { TAIL ~ a second closed position }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL