Cheyenne's Big Boy is located in Holiday Park, Cheyenne, Wyoming. Twenty-five Big Boys, the world's largest
steam engines, were built exclusively for Union Pacific by ALCO in Schenectady, New York between 1941 and 1944.
Each locomotive was 132 feet long and weighed 1,200,000 pounds.
The 25 Big Boys were the only locomotives to have the 4-8-8-4 wheel arrangement, with two sets of eight driving wheels, a four-wheel leading truck for stability entering curves and a four-wheel trailing truck to support the large firebox.
Gram and Pops visited here in October 2006.
Click here for pictures of Gram and Pops' Trip