Union Pacific's Two-Tone Gray 4-6-6-4 Challengers

This page was last updated on June 17, 2021.

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UP 3975-3984, renumbered to UP 3708-3717 (10 locomotives)

Union Pacific had 10 two-tone gray 4-6-6-4 Challengers. These 10 locomotives were part of a group of 13 oil-burning 4-6-6-4 Challengers that UP re-assigned beginning in December 1946 from Southern California on UP's South-Central District, to the Northwestern District. The new service was between Seattle and Portland, and along the Columbia River to Huntington. This group of passenger Challengers included UP 3940, 3944, and 3968, along with the 10 locomotives in the 3975-3984 group.

In their new assignment, the newly-arrived Challengers eliminated the use of helpers and double-headers on passenger trains on UP's Northwestern District, displacing older 4-8-2 Mountains and other smaller power for other duties. Although reassigned in December 1946, some of the 13 locomotives remained in California service for some months after, as late as mid 1947. Locomotives still in California included UP 3981 and 3984, which are shown on AT&SF dispatcher train sheets in August 1947 operating as motive power on alternating days on UP's Pony Express, trains 37 and 38 (237 and 238 on AT&SF over Cajon Pass).

For the two-tone gray locomotives, UP 3976 was the first to receive two-tone gray paint. It was completed in mid December 1946, and used for the first time to pull the eastbound Portland Rose, departing Portland on December 13, 1946. The story goes that Omaha directed Albina Shop in Portland to repaint the 3976 in gray, photograph it, and send the photo to Omaha for approval. Headquarters liked the new paint job and promptly wired the shop to repaint the rest of the series assigned to the pool. However, the three lower-numbered Challengers, UP 3940, 3944, and 3968, did not receive two-tone gray.

Of the 10 Challenger locomotives in the UP 3975-3984 series, photo research has confirmed that all ten were painted to two-tone gray in 1946, apparently with yellow stripes and lettering.

Along with two-tone gray paint, all ten locomotives also received smoke lifters, known to UP as "wind wings", a new feature added after October 1945 and intended to keep smoke out of the cabs and away from the operating crews. (Two other Challengers, UP 3943 and 3967, also received wind wings in 1948, to test the concept on coal-burning locomotives assigned to freight service.)

The result of the photo research documented in the table below shows that few photos exist of UP 3979 and 3980 in two-tone gray paint. However, the video produced by Video Rails about UP's Challengers shows that UP 3977, 3979 and 3980 were indeed in two-tone gray paint, with yellow striping and lettering.

The 10 two-tone gray Challengers operated mostly in passenger service, but there are photos of the locomotives in freight service. All photos of the locomotives in two-tone gray show them in service on the Northwestern District, at least until they were displaced in 1950 by additional E7 and E8 diesel locomotives. At that time they were shopped, repainted black, and reassigned to Utah and Wyoming as helpers.

It was reported in June 1951 that "several" 4-6-6-4 locomotives were working in the Council Bluffs area. They were equipped with smoke lifters and had previously been assigned to passenger service out of Portland, Oregon. (The Mixed Train, Volume 1, Number 1, June 1951)

In 1952 the locomotives were renumbered from the 3975-3984 series to the 3708-3717 series, but no photos have been found that show a 3700-class Challenger in two-tone gray paint.

The passenger Challengers had been built as coal burners in 1943, and were converted to oil burners in 1945 specifically for passenger service on the Northwestern District. They remained as oil burners after being renumbered into the 3700 series and until retirement in 1958-1961.

This series is notable because many were assigned as helpers on the Wasatch grade in Weber and Echo canyons, and were some of the last Union Pacific steam locomotives to operate in Utah.

Road
Number		 Paint Scheme Smoke
Wings		 Photo
Date		 Source
(see below)		 Notes
Two-Tone
Gray Paint		 Black
Paint
UP 3975   X - 1943 (8) p. 90 Omaha, Nebraska; as delivered
UP 3975   X - Dec 1945 (2) p. 86 Los Angeles, California; before gray paint
UP 3975 X   X Jul 1948 (8) p. 120 (no location)
UP 3976 X   X Dec 1946 (8) p. 120 Portland, Oregon; official photograph
UP 3976 X   X May 1949 (4) p. 96 Near Hood River, Oregon; freight service
UP 3976   X X Jul 1949 (2) p. 87 Portland, Oregon.
UP 3977   X X Oct 1945 (8) p. 92 Los Angeles, California; detail of new smoke wings
UP 3977   X X Oct 1945 (8) p. 119 Los Angeles, California; front; new smoke wings
UP 3977   X X Jan 1946 (2) p. 88 Los Angeles, California; before gray paint
UP 3977 X   X Feb 1948 (4) p. 99 Sumner, Washington.
UP 3977   X X Aug 1951 (9) p. 22 Wyoming, Wyoming.
UP 3978   X - 1947 (2) p. 90 Los Angeles, California; before gray paint
UP 3978  X   X May 1947 (4) p. 89 Huntington, Oregon.
UP 3979   X - Dec 1945 (8) p. 129 Los Angeles, California; before gray paint
UP 3979   X X early 1946 (8) p. 120 Los Angeles, California; before gray paint
UP 3979   X - 1946 (2) p. 91 Los Angeles, California; before gray paint
UP 3979 X   X Spring 1949 911) p. 255 Juniper, Oregon/Train 151
UP 3980   X - Aug 1946 (2) p. 92 Portland, Oregon; before gray paint
UP 3980   X X Apr 1950 (5) p. 66 Hermosa Tunnel, Wyoming.
UP 3980   X X Dec 1951 (1) p. 122 Evanston, Wyoming.
UP 3980   X X Jun 1952 (5) p. 91 Near Sherman, Wyoming.
UP 3981   X - Jun 1943 (2) p. 93 (no location); new, en route to UP
UP 3981   X - (no date) (8) p. 128 South Central District; before gray paint
UP 3981   X - (no date) (8) p. 128 Ogden, Utah; before gray paint
UP 3981 X   X 1950   (online photo at Tacoma by F. B. Thompson)
UP 3982 X   X Jun 1947 (2) p. 94 Portland, Oregon.
UP 3982   X X Aug 1951 (9) p. 23 Wyoming, Wyoming.
UP 3982 X   X Aug 1948 (8) p. 121 Portland, Oregon.
UP 3983 X   X Aug 1947 (2) p. 95 Portland, Oregon.
UP 3983 X   X Aug 1947 (6) p. 50 Portland, Oregon.
UP 3984 X   X 29 Apr 1948 (13) p. 33 Portland, Oregon.
UP 3984 X   X Jul 1948 (8) p. 121 Seattle, Washington.
UP 3984 X   X Aug 1948 (2) p. 96 Portland, Oregon.
UP 3984   X X Oct 1951 (5) p. 83 Hermosa, Wyoming.
Road
Number		 Paint Scheme Smoke
Wings		 Photo
Date		 Source
(see below)		 Notes
Two-Tone
Gray Paint		 Black
Paint
UP 3708   X X Mar 1953 (2) p. 86 ex 3975; Ogden, Utah
UP 3708   X X Oct 1953 (3) p. 103 ex 3975; Uintah, Utah
UP 3708   X X Oct 1958 (10) front-sheet ex 3975; Castle Rock, Utah
UP 3708   X X Oct 1958 (10) p. 179 ex 3975; Emory, Utah
UP 3709   X X 1952 (2) p. 87 ex 3976; Seattle, Washington.
UP 3709   X X 11 Apr 1954 (12) p. 124 ex 3976; Buford, Wyoming.
UP 3710   X X (no date) (7) p. 66 ex 3977; (no location)
UP 3710   X X Mar 1953 (2) p. 88 ex 3977; Ogden, Utah
UP 3710   X X Oct 1958 (8) p. 141 ex 3977; Wasatch, Utah
UP 3710   X X summer 1959 (10) p. 158 ex 3977; Baxter, Wyoming.
UP 3711   X X Apr 1954 (2) p. 90 ex 3978; North Platte, Nebraska.
UP 3712   X X Oct 1954 (2) p. 91 ex 3979; Laramie, Wyoming.
UP 3712   X X summer 1959 (10) p. 158 ex 3979; Baxter, Wyoming.
UP 3713   X X Jun 1956 (2) p. 92 ex 3979; Ogden, Utah
UP 3713   X X Oct 1957 (7) p. 69 ex 3980; Cheyenne, Wyoming.
UP 3714   X X Jul 1953 (14) Trainorders.com, November 30, 2017
UP 3714   X X Jul 1954 (2) p. 93 ex 3981; Ogden, Utah
UP 3715   X X Oct 1956 (2) p. 94 ex 3982; Ogden, Utah
UP 3715   X X Jul 1959 (3) p. 43 ex 3982; Cheyenne, Wyoming.
UP 3716   X X Mar 1954 (2) p. 95 ex 3983; North Platte, Nebraska.
UP 3717   X X Oct 1957 (2) p. 96 ex 3984; Ogden, Utah
UP 3717   X X Oct 1958 (8) p. 115 ex 3984; Ogden, Utah
UP 3717   X X Oct 1958 (10) p. 178 ex 3984; Echo, Utah

Photo Sources

  1. Drury, George. Union Pacific Across Sherman Hill (Kalmbach, 2000)
  2. Ehernberger, James L. Challenger Portraits (Challenger Press, 1993)
  3. Ehernberger, James L. and Francis G. Gschwind. Union Pacific Steam, Eastern District (E&G Publications, 1975)
  4. Ehernberger, James L. and Francis G. Gschwind. Union Pacific Steam, Northwestern District (E&G Publications, 1977)
  5. Ehernberger, James L. and Francis G. Gschwind. Sherman Hill (E&G Publications, 1973)
  6. Grenard, Ross B. "Greyhounds of the Overland Trail" Railfan & Railroad, January 1988, Volume 7, Number 1, pages 48-53
  7. Grenard, Ross, and John Krause. The Overland Route (Carstens Publications, no date)
  8. Kratville, William W. The Challenger Locomotives (Kratville Publications, 1980)
  9. Olmstead, Robert. The Big Guys (Robert P. Olmstead, 1998)
  10. Pfeifer, Jack. West From Omaha (Pacific Fast Mail, 1990)
  11. Asay, Jeff. Union Pacific Northwest (Pacific Fast Mail, 1991)
  12. Schmitz, Lou. UP Color Guide to Freight and Passenger Equipment, Volume 2 (Morning Sun, 1996)
  13. Schumacher, David. The "Overland" Union Pacific Overland, Service Cars and Their Paint Schemes". Prototype Modeler, Volume 4, Number 1, August 1980, page 24.
  14. Trainorders.com (subscription web site)

Sources Without Challenger Photos

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