The rules that use the category "<line_type-sing>" are:

<new_line>

<det-indef-sing> <color> <line_type-sing>

<det-indef-sing> <line_type-sing>

<line_type-sing>

<line_name>

<line_type-sing>

<line_type-sing> <line_id>

the <line_type-sing>