Union Pacific 3985

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Union Pacific 3985
Union Pacific Challenger 3985 01.jpg
UP 3985 running through Alton, Iowa in October 2008
Type and origin
Power type Steam
Builder American Locomotive Company (ALCO)
Serial number 70174
Build date July 1943
Configuration 4-6-6-4
UIC classification (2′C) C2′ h4
Gauge 4 ft 8 12 in (1,435 mm) standard gauge
Driver diameter 69 in (1,753 mm)
Weight on drivers 404,000 lb (183,000 kg; 183 t)
Locomotive and tender
combined weight
1,073,900 lb (487,100 kg; 487.1 t)
Boiler pressure 280 lbf/in2 (1.93 MPa)
Cylinders Four
Cylinder size 21 in × 32 in (533 mm × 813 mm)
Performance figures
Power output 5,000 hp (3,700 kW)
Tractive effort 97,352 lbf (433.04 kN)
Factor of
Operator(s) Union Pacific Railroad
Class 4664-4
Number in class 11 of 25
Number(s) UP 3967, UP 3718, UP 3985
Nicknames "Challenger"
Retired 1962
Restored 1981
Disposition Union Pacific Heritage Fleet, based on Cheyenne, Wyoming, at roundhouse

Union Pacific 3985 or UP 3985 is a four-cylinder simple articulated 4-6-6-4 Challenger-type steam locomotive owned by Union Pacific Railroad. It was built in 1943 by the American Locomotive Company of Schenectady, New York. The locomotive is one of only two of the original 105 Union Pacific Challengers in existence, the other being UP 3977 on static display in North Platte, Nebraska. Before it was stored, it was the largest and heaviest operational preserved steam locomotive in the world.[1]


Designed by UP chief mechanical engineer Otto Jabelmann in 1941, UP 3985 was part of the second order of this second version of the Challenger. The design drew on recent experience with the enormous 4-8-8-4 Big Boy locomotives, and resulted in a locomotive in working order weighing some 317 short tons (288 t; 283 long tons) accompanied by a tender weighing 174 short tons (158 t; 155 long tons) when 2/3 loaded. Calculated tractive effort is 97,350 lbf (433.0 kN). The Challenger class was intended to speed up freight operations on the 0.82% grades across Wyoming; the 1.14% Wasatch climb east from Ogden was to be conquered by the Big Boys without helpers. The Challengers and Big Boys arrived on the scene just as traffic was surging in preparation for American participation in World War II.

UP 3985 Westbound at Sloat, California, 2005

Service and Restoration[edit]

UP 3985 operated in its last "regular" train service in 1957.[1] The locomotive was retired about 1962 and after many years of storage in a roundhouse at Cheyenne, Wyoming, UP 3985 was placed on an outdoor display beside the Cheyenne depot in 1975. Beginning in 1979, a group of Union Pacific employee-volunteers started work on restoring the locomotive, and it was returned to operational condition in 1981.[1] Originally a coal-burner, to prevent lineside grass fires it was successfully converted to oil firing in 1990 plus in 1992 the union pacific 3985 challenger was selected to pull the very special 50th running of the CSX Santa Claus special train on former clinchfield rails from Kentucky to kingsport Tennessee and got relettered and renumbered to clinchfield railroad #676 for the occasion .Stationed at Cheyenne with other equipment in the UP's heritage collection, it's currently used for excursion trains and occasionally mainline freight on ferry moves. It was in the maintenance shop at Cheyenne in 2007 and underwent necessary repairs for service in 2008. In September 2010, 3985 was selected to pull the Ringling Brothers and Barnum & Bailey Circus Train from Cheyenne to Denver, Colorado, where the circus held a special performance to celebrate P.T. Barnum's birthday. It last ran in October, 2010 and since then has been stored in Cheyenne.


  1. ^ a b c "The History of the Challengers". www.uprr.com. Retrieved 2009-03-23. 
  • Ehernberger, "Challenger Portraits", Challenger Press, Cheyenne, WY, 1993.
  • Kratville, "The Challenger Locomotives", Kratville Publications, Omaha, NE, 1980.

External links[edit]