File:Walschaerts motion.gif

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Walschaerts valve gear in a steam locomotive. In this animation, the red colour represents live steam entering the cylinder, blue represents expanded (spent) steam being exhausted from the cylinder. Note that the cylinder receives two steam injections during each full rotation; the same occurs in the cylinder on the other side of the engine.

Already a featured picture, but would make a good image on the trains portal as well. Bob talk 19:16, 27 January 2010 (UTC)