<page_title> 5 ft 6 in gauge railway </page_title> <section_title> Operational Installations </section_title> <table> <cell> United States <col_header> Country/territory </col_header> </cell> <cell> Bay Area Rapid Transit (BART) San Francisco Bay Area <col_header> Railway </col_header> </cell> <cell> 109 mi (175 km) <col_header> Route length </col_header> </cell> <cell> operating <col_header> Notes </col_header> </cell> </table>
The Bay Area Rapid Transit system is the only operating railroad in the United States to use 1,676 mm (5 ft 6 in) gauge, with 109 miles (175 km) of tracked routes.