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