Alaska Railroad No. 556 is an S-160 class 2-8-0 "Consolidation" type steam locomotive built by the Baldwin Locomotive Works of Philadelphia, PA in 1943, originally for the U.S. Army Transportation Corps (USATC). It is one of several S-160 class 2-8-0 type locomotives built by Baldwin, ALCO, and Lima for the U.S. Army between 1942 and 1945 for use in Europe and Africa during World War II. It would later be sold in 1945 to the Alaska Railroad along with eleven others of this locomotive type and was renumbered to 556.
For 13 years, No. 556 hauled passengers and freight from Seward through Anchorage and on to Fairbanks before being taken out of service in 1958. In 1959, No. 556 was taken out of storage and moved to Delaney Park in Anchorage to be used as an educational and climbing display for children.
In 2015 the locomotive was cosmetically restored and converted into a "static display" piece rather than a climbable display mostly for safety and environmental reasons. The main goal was to improve the existing site, including adding on a safety fence around the static display, updated informational signage on the history of No. 556, and an accessible walkway.
While this was underway, several of No. 556 operational components were removed and replaced with replicas. These removed parts were used to aid in the restoration of its sister engine Alaska Railroad No. 557.