<page_title> HO scale </page_title> <section_title> Track </section_title> <table> <cell> 16.5 mm (0.65 in) <col_header> Track gauge </col_header> </cell> <cell> Standard gauge <col_header> Prototype gauge </col_header> </cell> </table>
For HO scale, a track of 16.5 mm was used to represent the prototypical standard gauge track.