Two empty container railway wagons with <a href="//commons.wikimedia.org/wiki/Railway_coupler" title="Railway coupler">buffers and chain coupling</a>; seen from the top.
<a href="//commons.wikimedia.org/wiki/User:Spielvogel" title="User:Spielvogel">Spielvogel</a>
<span class="int-own-work" lang="en">Own work</span>