Certain portions of {HEAD ~ the engine}, such as {TAIL ~ the flywheel}, are left out of FIGS 4 6 to simplify the drawing 
Certain portions of { HEAD ~ the engine } , such as { TAIL ~ the flywheel } , are left out of FIGS 4 6 to simplify the drawing
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH