This is the accordion section of an articulated Metro bus
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/49503074211@N01">Justin Baeder</a> from Seattle, USA
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/49503074211@N01/184593469/">Middle of the Bus</a>