Pennsylvania Railroad 520 is a 2-8-2 "Mikado" type steam locomotive built in 1916 by the Baldwin Locomotive Works for the Pennsylvania Railroad for freight duties as a member of the L1s class. In 1942, the locomotive was involved in a devastating boiler explosion incident that required construction of a new, replacement boiler. After being retired in 1957, the locomotive was saved for preservation and placed on display at the Railroad Museum of Pennsylvania in Strasburg, Pennsylvania, and was listed on the National Register of Historic Places in 1979.