Note that the carriage can move past the support members 19 to {HEAD ~ a position} at the left hand end of {TAIL ~ the beam} 
Note that the carriage can move past the support members 19 to { HEAD ~ a position } at the left hand end of { TAIL ~ the beam }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL