Bar line thickness

Adjusting LilyPond bar line thickness does nothing.

   \new Staff {
      c'1
      c'1
      c'1
      \override Staff.BarLine #'color = #red
      \override Staff.BarLine #'thickness = #0.5
      c'1
   }

Adjusting bar line hair-thickness does the trick.

   \new Staff {
      c'1
      c'1
      c'1
      \override Staff.BarLine #'color = #red
      \override Staff.BarLine #'hair-thickness = #0.5
      c'1
   }