“Big Boy” is the World’s Largest Successful Steam Locomotive
Known as a “Big Boy” because of its immense size and power, Union Pacific Railroad #4006 is one of the world’s largest successful steam locomotives.
Built in 1941 by the American Locomotive Company at a cost of $265,000.00 and with a total weight of over 600 tons, Number 4006 is one of 25 Big Boys. It is 132′ 9 1/4″ long, carries 33 tons of coal and 25,000 gallons of water in its tender. It is a 4-8-8-4 (simple) articulated locomotive.
Roll on over and visit Big Boy at the Museum of Transportation in St. Louis, Missouri!