Let 'Big Boy' speed your freight - Union Pacific Railroad (Train)- Framed Picture - 11" x 14"
Big Boy is the popular name of the American Locomotive Company 4000-class 4-8-8-4 articulated, coal-fired, steam locomotives manufactured between 1941 and 1944 and operated by the Union Pacific Railroad until 1959.
The Big Boy fleet of twenty five locomotives were used primarily in the Wyoming Division to haul freight over the Wasatch mountains between Green River, Wyoming and Ogden, Utah.
They were the only locomotives to use a 4-8-8-4 wheel arrangement consisting of a four-wheel leading truck for stability entering curves, two sets of eight driving wheels and a four-wheel trailing truck to support the large firebox.
According to a Union Pacific executive, the 4-8-8-4 series originally was to have been called "Wasatch". One day while one of the engines was being built an unknown worker scrawled "Big Boy" in chalk on its front. With that, the legendary name was born and has stuck ever since.