The Soviet-built opposed-piston <a href="https://en.wikipedia.org/wiki/2-10-4" class="extiw" title="en:2-10-4">2-10-4</a> of 1949.
<a rel="nofollow" class="external text" href="http://www.aqpl43.dsl.pipex.com/MUSEUM/LOCOLOCO/russ/russrefr.htm">Click here to read about this and other strange Soviet locomotives.</a>
Раков "Локомотивы отечественных железных дорог 1845-1955".