Union Pacific No. 3977

Union Pacific 3977 4-6-6-4 "Challenger" Steam Locomotive
Union Pacific Challenger No. 3977, preserved in its 1940s Greyhound livery, on static display at Cody Park in North Platte, Nebraska.
Specifications
Road Number	3977
Class	Challenger
Builder	American Locomotive Company (ALCO), Schenectady, NY
Build No. & Date	Serial No. 70472, built in 1943
Wheel Configuration	4-6-6-4 (Heavy Challenger Type)
Simple articulated (not compound), designed for high-speed freight and passenger service
Driver Diameter	69 inches
Working Boiler Pressure	280 psi
Tractive Effort	97,350 lbf (108,650 lbf with booster, if equipped)
Fuel Type	Originally coal; converted to oil in 1952
Valve Gear	Walschaerts
Wheelbase	73 ft 6 in (overall with tender)
Loco & Tender Length	Approximately 121 ft
Career
Disposition	Preserved and on static display at Cody Park, North Platte, Nebraska
Original Railroad	Union Pacific Railroad
Retired	1958 (renumbered as 3710 during final service years)
Restored	Static restoration with Greyhound paint scheme (late 1960s–1970s)

Union Pacific No. 3977 is a 4-6-6-4 "Challenger"-type steam locomotive built in 1943 by the American Locomotive Company (ALCO) in Schenectady, New York. It was part of a group of 25 locomotives (Nos. 3975–3999) ordered that year by the Union Pacific Railroad. These simple articulated locomotive were designed to replace earlier compound designs like the 4-12-2, offering higher speeds and reduced reciprocating mass—capable of reaching speeds above the 50 mph limit imposed on the older types.

No. 3977 was among a select group of ten Challengers that were painted in the striking two-tone gray and yellow passenger livery, often referred to as the "Greyhound" scheme. Outfitted with smoke deflectors, it was used in passenger service beginning in 1946, pulling trains between Portland, Oregon, and Seattle, Washington, and along the Columbia River route to Huntington, Oregon.

In 1952, the locomotive was converted from coal to oil-burning. During this process, its five firebox circulators were removed and replaced with oil firepans. It was renumbered to No. 3710 during this period.

Following its retirement in 1958, No. 3710 was saved from scrapping and donated to the city of North Platte, Nebraska. It was later renumbered back to its original number, 3977, and placed on display at Cody Park in October 1968. Although it initially arrived in standard Union Pacific black with a graphite smokebox, it was eventually repainted in its iconic two-tone passenger livery to reflect its earlier role in the northwest.

Trivia

• 3977 is one of only two surviving 4-6-6-4 Challengers—the other is No. 3985, also built in 1943.
• In 1959, still under the number 3710, it worked alongside Union Pacific 844 at Bailey Yard in Omaha, Nebraska, helping clear snow from the tracks using its steam heat. It was also renumbered to 900079 for this purpose, and declassified from a locomotive to roadway equipment on Union Pacific's books.
• On October 28, 1956, it was seen providing helper service by pushing a freight train.
• It is currently preserved and on static display alongside Centennial Locomotive No. 6922.
• In 1990, 3977's oil pan was removed and placed inside 3985's firebox because it was being converted from coal to oil. A new one had to be fabricated in order to complete the appearance of the locomotive.
• Although well-preserved, a return to operation is unlikely.

Gallery

List of Union Pacific Challenger Locomotives
CSA-1:	3900 (3800) • 3901 (3801) • 3902 (3802) • 3903 (3803) • 3904 (3804) • 3805 • 3906 (3806) • 3807 • 3808 • 3909 (3809) • 3910 (3810) • 3911 (3811) • 3912 (3812) • 3913 (3813) • 3914 (3814)
CSA-2:	3815 • 3816 • 3817 • 3918 (3818) • 3819 • 3820 • 3821 • 3822 • 3823 • 3822 • 3823 • 3824 • 3825 • 3826 • 3827 • 3828 • 3829 • 3830 • 3831 • 3832 • 3833 • 3834 • 3835 • 3836 • 3837 • 3838 • 3839
4664-3:	3950 • 3951 • 3952 • 3953 • 3954 • 3955 • 3956 • 3957 • 3958 • 3959 • 3960 • 3961 • 3962 • 3963 • 3964 • 3965 • 3966 • 3967 • 3968 • 3969
4664-4:	3975 • 3976 • 3977 • 3978 • 3979 • 3980 • 3981 • 3982 • 3983 • 3984 • 3985 • 3986 • 3987 • 3988 • 3989 • 3990 • 3991 • 3992 • 3993 • 3994 • 3995 • 3996 • 3997 • 3998 • 3999
4664-5:	3730 • 3731 • 3732 • 3733 • 3734 • 3735 • 3736 • 3737 • 3738 • 3939 • 3740 • 3741 • 3742 • 3743 • 3744 • 3745 • 3746 • 3747 • 3748 • 3749
Clinchfield Railroad:	Locomotive Type
Extinct:	Fetter Challengers
Excursion Star:	3967 • 3985
Preserved:	3977 • 3985