HOW TO USE LINE TOOL TO CREATE HACHURE LINES?

I am a mapmaker, and I need PhotoShop to make hachure lines for me automatically. Hachures are the old-fashioned representation of ridges, by means of short, parallel lines, packed close together, which go down each side of a topographic ridge. I have many features which I need to label this way over the top of an airphoto. I would like to use the Line Tool to draw the ridge lengthwise, then have PS create the small, parallel lines across the line I draw. These are sometimes referred to as "caterpillars" because they look like that. Thank you!