This preserved Metropolitan carriage was part of the 'Chesham Stock' type, which worked on (obviously) the Chesham line of the Metropolitan Railway network. Here it is, preserved and working, on the Bluebell Railway.
<a href="//commons.wikimedia.org/wiki/User:Bradley_Wurth" class="mw-redirect" title="User:Bradley Wurth">Bradley Wurth</a>
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<span class="int-own-work" lang="en">Own work</span>