{TAIL ~ The indicator} is swept over {HEAD ~ the brake block} to detect variations of the inside brake block surface from the specified radius 
{ TAIL ~ The indicator } is swept over { HEAD ~ the brake block } to detect variations of the inside brake block surface from the specified radius
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH