Challenger Goes for a Ride

OMAHA, Neb. – For the first time in its 60-year history, Union Pacific Railroad’s “Challenger” No. 3985, the world’s largest operating steam locomotive, made a passenger run between Cheyenne, Wyo., and Joyce, Neb. July 12.

The one-day public steam excursion celebrated railroad heritage on a Union Pacific line that has not seen an operating steam locomotive or passenger train in over 50 years. The Challenger pulled a 16-car passenger train.

Union Pacific’s No. 3985, an articulated locomotive with a “hinged” frame to allow it to negotiate curves, is 122 feet long. It weighs more than one million pounds, has six-foot-diameter drive wheels and can reach a top speed of 70 miles per hour. The locomotive was built in 1943 for fast freight service and retired in 1959. In 1981, it was restored to running condition for special service by UP employee volunteers. The Challenger is based in Cheyenne, Wyo.

The Sherman Hill Model Railroad Club sponsored the excursion.

Union Pacific Challenger No. 3985 was designed by Union Pacific and built in 1943 by the American Locomotive Company. It is one of 105 Challengers built for Union Pacific between 1936 and 1943 and is the only operating engine of its class in the world today–the largest and most powerful operating steam locomotive.

No. 3985 last operated in “regular” train service in 1957. It was retired in 1962 and stored in the roundhouse in Cheyenne, Wyoming, until 1975, when it was placed on display near the Cheyenne depot. A group of Union Pacific employees volunteered their services to restore the locomotive to running condition in 1981.

The name Challenger was given to steam locomotives with a 4-6-6-4 wheel arrangement. This means that they have four wheels in the leading “pilot” truck, which helps guide the locomotive into curves; two sets of six “driving” wheels, and finally, four “trailing” wheels, which support the rear of the engine and its massive firebox. Each set of driving wheels has its own steam cylinder. The result, in essence, is two engines less than one boiler.

The Challengers were designed for fast freight service, but occasionally pulled passenger trains. No. 3985 originally burned coal and pulled a tender with a 32-ton capacity. In 1990, it was converted to use No. 5 oil. The top speed of No. 3985 is about 70 miles an hour.