A tribute to the "Big Boy" locomotives produced by Union Pacific, "Last of the Giants" shows the end of a memorable era in Western Railroading, you'll see the development of steam power on the Union Pacific from 4-6-0s, 2-8-0s, and 2-8-2s up to 2-10-2s and even 4-12-2s, shown through film, photos and animated diagrams. This is followed by the development of compound articulated Mallets and simple articulateds such as the Challengers.

Measuring 132 feet long and weighing one and one-quarter million pounds, the Big Boys were appropriately named. These were the largest and heaviest of their type and could pull a loaded 5-1/2 mile long train on level track. Their tenders carried a massive 28 tons of coal and 25,000 gallons of water; and with a heavy train a Big Boy could use all of this up in the first half of a 57-mile rum. Although there were only 25 Big Boys ever built, they ran up a total of nearly 26 million miles in 18 years, hauling billions of tons.

The following silent documentary film "Big Boy and his Brothers" shows the big steam locomotives of the Union Pacific Railroad. Shot by Gene Miller primarily in western Nebraska, Wyoming and Colorado, this film gives a rare look at some of the largest locomotives ever built. It includes images of the 4-12-2s known as the "Union Pacifics" at 2:43, the largest non-articulated locomotives at the time they were made, and featured 67-inch drivers. At 5:14, a 4-6-6-4 Challenger type is seen, introduced in 1936. The 4-8-4 engines are shown starting at 8:24, including the 800 series Nevada type that could pull 20 Pullman cars at 70 mph. At 12:17, the 4-8-8-4 Big Boys are shown.

The Big Boy fleet of twenty five locomotives were used primarily in the Wyoming Division to haul freight over the Wasatch mountains between Green River, Wyoming and Ogden, Utah. Postwar increases in the price of both coal and labor and the efficiency of diesel-electric motive power foretold a limited life for the Big Boys, but they were among the last steam locomotives taken out of service. Towards the end of their career, the Big Boys could still pull more than their rated tonnage of 6,573 short tons (5,963 t). The Big Boys' ratings were increased several times until they regularly pulled 8,727 short tons (7,917 t) over the Wasatch range.

The last revenue train hauled by a Big Boy ended its run early in the morning on July 21, 1959. Most were stored operational until 1961 and four remained in operational condition at Green River, Wyoming until 1962. Their duties were assumed by diesel locomotives and gas turbine-electric locomotives. Of the 25 Big Boy locomotives manufactured, eight remain. Seven of the eight surviving Big Boys are on static display. One, number 4014, is undergoing a restoration to operating condition for excursion service which includes conversion to No. 5 oil firing.