The roughly 100 hundred miles that separates Denver, Co, and Cheyenne, Wy is the currently epicenter of Union Pacific’s monster steam locomotive the Big Boys, not because they routinely ran between these two cities but because three of the eight existing Big Boys can be found along Highway 25 in the cities of Denver and Cheyenne.
Cheyenne was the operational headquarters for the 4-8-8-4, freight locomotives that were designed to tackle the Wasatch Mountains between Cheyenne and Ogden, Ut. These were the largest steam locomotives ever built.
Overall, 25 Big Boys were made, currently two are found in Cheyenne and one in Denver. No. 4004 can be seen on display in Holiday Park in Cheyenne. Local residents petitioned Union Pacific to donate a Big Boy to the city of Cheyenne when they saw the rapid disappearance of stream locomotives from the rails in the late 1950s and early 1960s.

Big Boy No. 4005 had a much more colorful history than 4004. 4005 was only one of two Big Boys that were converted from coal to oil (more on that other converted Big Boy later). 4005 tallied up 1,043,624 road miles in a 20 year career. The giant is also the only Big Boy to ever be involved in a major accident. On April 27, 1953, 4005 hit an opened siding at 50 miles per hour causing the train to derail and the Big Boy fell on it’s left side (the damage is still visible today). The engineer, fireman, head-end brakemen were all killed in the wreck. The locomotive was later repaired in Cheyenne and returned to service.
The 4005 is now on display in Denver’s Forney Museum of Transportation in northern Denver. This is where I returned, this time with Steve, to do a few field sketches of the Big Boy (the featured sketch and the sketch below of 4005’s tender.)

The other Big Boy that was converted to burning oil is perhaps the most famous Big Boy: Union Pacific’s 4014. 4014 is the largest operational steam locomotive in the world. It was on display for many years in California and was shipped, by rail, to the steam shop in Cheyenne and fully restored to working order.

Union Pacific 4014 has proven to be the most illusive Big Boy for me. You would think the largest operational steam locomotive in the world would be easier to see! I have seen the Steam Shop in Cheyenne and the doors have always been closed, hiding 4014 and the Living Legend No. 844. A west coast steam tour was planned for this summer but was cancelled because UP’s rails are crowded with freight traffic to ease the supply chain issues. Yet another opportunity missed to see 4014 under steam.
