D49 Lever

The D49 series (D for"depot"type, passenger service) is a class of Soviet 2-10-2 (1-5-1 in Russian notation) passenger steam locomotives, nicknamed"Рычаг"(Rychag), meaning"Lever"in Russian. This distinctive name originated from the locomotive’s unique lever-type valve gear – a modified Walschaerts valve gear with an additional articulated lever system, designed to improve steam distribution efficiency and reduce maintenance complexity.