Duluth Missabe and Iron Range Yellowstone Mallet #229 was one of eighteen locomotives of its type built by the Baldwin Locomotive Works at Eddystone, Pennsylvania, in two contracts of eight in 1941 and ten more in 1943. Built during World War II, when iron ore was vital for ships, tanks, and other military equipment, these locomotives received an A-1-A preference rating for construction materials because of their importance in moving ore, leading to their reputation as "the locomotives that defeated Hitler." Number 229, the second locomotive in the 1943 group numbered 228 through 237, was completed and test run on January 5, 1943, and scheduled to leave the Baldwin plant on January 9. Because the Minnesota ore season was closed for winter, it was sent instead to Denver, Colorado, to be leased to the Denver Rio Grande and Western Railroad, where it pulled long freight trains over the Rocky Mountains and Continental Divide before returning in 1943 to begin work on the Iron Range Division at Two Harbors. Only seventy-two Yellowstone locomotives were ever built in the U.S., operated by the Baltimore and Ohio, Northern Pacific, Southern Pacific, and Duluth Missabe and Iron Range. The Duluth Missabe and Iron Range Yellowstones were 128 feet long, weighed more than 400 tons without coal or water, carried twenty-six tons of coal and 25,000 gallons of water in the tender, and had a working weight of almost a million pounds; with steam pressure of 240 pounds per square inch, they produced a tractive effort of 140,000 pounds. Compared with the Union Pacific Big Boy, they had smaller driving wheels that gave them great power at slower speeds, and on this heavy railroad they could pull trains that would require four diesel locomotives today. After the last regular ore run by a Yellowstone Mallet, made by #222 on July 5, 1960, #229 eventually replaced #221 on display at Two Harbors in 1967 after having been stored in the Proctor roundhouse, and in 2011 it underwent a complete cosmetic restoration. Together, the 3 Spot and #229 represent the first and last stages in the evolution of the steam locomotive on Minnesota's Iron Range.