One of the finest and fastest steam locos ever built, 4-6-4 Hudsons could found at some point on some of America's most important passenger trains. Introduced in the late 1920s, the engines were equipped with a larger firebox and huge drivers. Built for speed and power, they could easily race trains of heavyweight cars across country. When streamlining became the rage, both older and brand-new engines were fitted with metal shrouds designed to match the new lightweight trains.