When mounting side guiding rails on vertical wall surfaces of a building it is often problematic to correctly align and space {HEAD ~ the various mounting brackets} used in {TAIL ~ the mounting} of a single rail 
used in
When mounting side guiding rails on vertical wall surfaces of a building it is often problematic to correctly align and space { HEAD ~ the various mounting brackets } used in { TAIL ~ the mounting } of a single rail
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH