Wikipedia:POTD column/September 1, 2006



An animated image showing how a Walschaerts valve gear works. The red color represents live steam entering the cylinder, while the blue represents expanded (spent) steam being exhausted from the cylinder. Invented in 1844 by Egide Walschaerts, the Walschaert valve gear became the most commonly used gear in steam locomotives.

Image credit: R.A. Booty/Janke Archive - More featured pictures...