The unloading station includes a door moving mechanism for moving the doors of the vehicle to {TAIL ~ the open position} upon {HEAD ~ its arrival} at the station 
The unloading station includes a door moving mechanism for moving the doors of the vehicle to { TAIL ~ the open position } upon { HEAD ~ its arrival } at the station
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH