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