Highgate tube station
... that Highgate tube station had platforms built to accommodate nine-car trains on the Northern line that never used them?
... that <b id="mwBY8"><a href="./Highgate_tube_station" id="mwBZA" rel="mw:WikiLink" title="Highgate tube station">Highgate tube station</a></b> had platforms built to accommodate nine-car trains on the <a href="./Northern_line" id="mwBZE" rel="mw:WikiLink" title="Northern line">Northern line</a> that never used them?