{HEAD ~ means} for positioning {TAIL ~ the brake block} so that the first measuring point on the brake block is aligned with the first support surface and the second measuring point on the block is aligned with the second support surface 
for positioning
{ HEAD ~ means } for positioning { TAIL ~ the brake block } so that the first measuring point on the brake block is aligned with the first support surface and the second measuring point on the block is aligned with the second support surface
HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH