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