He's not bad, this Big-Boy!
Around 1940, Union Pacific was having trouble pulling its long freight convoys in the Wasatch Mountains of Wyoming. Several locomotives often had to be coupled together to overcome the difficulty. Hence the order for the largest steam locomotive ever built - to replace these wasteful, labor-intensive machines... The Big-Boy - according to legend, the name a worker wrote in chalk on one of the machines - was built by the Alco company between September 1941 and November 1944.
During tests in April 1943, the 4016 developed 8,000hp on the hook. The maximum speed of 128 km/h was also considerable for such locomotives (cruising speed was 50 km/h), and they were capable of routinely pulling 4,300-ton trains in the Rockies. They consumed 80 m³ of water and 11.4 t of coal per 100 km, and were therefore coupled to 7-axle centipede tenders. Total weight in service - locomotive & tender - was 541 tons. The machine measured 26 meters and 40.50 meters with the tender. The last Big Boy ran on July 21, 1959.
Twenty-five were built, some of which are now in museums...
