A video still of a portion of a C stock route map showing that the Hammersmith &amp; City service was once part of the Metropolitan line.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/47739225@N08">citytransportinfo</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/citytransportinfo/50974061298/">C-MetLine-OnRteMap-VideoStill</a>