Big Boy No. 4014

Twenty-five Big Boys were commissioned exclusively for Union Pacific Railroad, the first of which was delivered in 1941. These massive locomotives were built to haul heavy equipment in support of the war effort, normally operating between Ogden, Utah, and Cheyenne, Wyoming. The Big Boys are 133 feet long and weigh 1.2 million pounds.

Due to their great length, the frames of the Big Boys are “hinged,” or articulated, to allow them to negotiate curves. They have a 4-8-8-4 wheel arrangement, which means they have four wheels on the leading set of “pilot” wheels to guide the engine; eight drivers on the first engine; another set of eight drivers on the second engine; and four wheels trailing that support the rear of the locomotive.

No. 4014 was retired in Dec. 1961 after traveling 1,031,205 miles. Union Pacific reacquired it from the RailGiants Train Museum in Pomona, California, in 2013 and relocated it back to Cheyenne, Wyoming, for a multi-year restoration. It returned to service in May 2019 to celebrate the 150th Anniversary of the Transcontinental Railroad's Completion.

The seven other remaining Big Boys are on public display in St. Louis, Missouri; Dallas, Texas; Omaha, Nebraska; Denver, Colorado; Scranton, Pennsylvania; Green Bay, Wisconsin; and Cheyenne, Wyoming.