The section now shows 13, 14, 15 and 18 on a third level with the
incline from the plant floor, instead of footnoting them as not drawn,
and the key runs 6-18 in number order in two columns. Sheet 6 moves the
incline to the plant's north end to match.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>