Union Pacific FEF Series

The Union Pacific FEF Series consists of forty-five 4-8-4 "Northern" steam locomotive types built by the American Locomotive Company (ALCO) between 1937 and 1944 and operated by the Union Pacific Railroad until 1959.

Union Pacific FEF Series
Union Pacific 844, Painted Rocks, NV, 2009 (crop).jpg
Union Pacific 844 running through Painted Rocks, Nevada on September 15, 2009
Type and origin
Power typeSteam
BuilderAmerican Locomotive Company (ALCO)
Build date1937–1944
Total produced45
 • Whyte4-8-4
 • UIC2′D2′ h2
Gauge4 ft 8+12 in (1,435 mm)
Driver dia.FEF-1: 77 in (1,956 mm),
FEF-2/3: 80 in (2,032 mm)
WheelbaseLoco & tender: 98 ft 5 in (30.00 m)
LengthLoco & tender: 114 ft 2+58 in (34.81 m)
Adhesive weightFEF-1: 270,000 lb (122.5 tonnes),
FEF-2: 265,520 lb (120.4 tonnes),
FEF-3:270,300 lb (122.6 tonnes)
Loco weightFEF-1: 465,000 lb (210.9 tonnes),
FEF-2: 478,640 lb (217.1 tonnes),
FEF-3: 490,700 lb (222.6 tonnes)
Total weightFEF-1: 830,150 lb (376.5 tonnes),
FEF-2: 894,960 lb (405.9 tonnes),
FEF-3: 912,250 lb (413.8 tonnes)
Fuel typeCoal from 1937 to 1946
No. 5 fuel oil from 1946 onwards
Fuel capacityCoal: 50,000 lb (22.7 tonnes),
Oil: 6,000 US gal (22,712.5 litres; 4,996.0 imperial gallons)
Water cap20,000 US gal (76,000 l; 17,000 imp gal)
 • Firegrate area
100 sq ft (9.3 m2)
Boiler86 316 in (2189.2 mm) diameter
Boiler pressure300 lbf/in2 (2.07 MPa)
Heating surface4,224 sq ft (392.4 m2)
 • Tubes2,204 sq ft (204.8 m2)
 • Flues1,578 sq ft (146.6 m2)
 • Firebox442 sq ft (41.1 m2)
 • TypeFEF-1/3: Type A
FEF-2: Type E
 • Heating area1,400 sq ft (130 m2)
Cylinder sizeFEF-1: 24.5 in × 32 in (622 mm × 813 mm),
FEF-2/3: 25 in × 32 in (635 mm × 813 mm)
Valve gearWalschaerts
Performance figures
Tractive effortFEF-1: 63,611 lbf (283.0 kN),
FEF-2/3: 63,800 lbf (283.8 kN)
Factor of adh.FEF-1/3: 4.24
FEF-2: 4.17
OperatorsUnion Pacific Railroad
ClassFEF-1, FEF-2, and FEF-3
NumbersFEF-1: 800–819,
FEF-2: 820–834,
FEF-3: 835–844
DeliveredFEF-1: 1937,
FEF-2: 1939,
FEF-3: 1944
Retired1958-1959 (but 844 never retired)
PreservedFEF-1: No. 814 preserved, remainder scrapped
FEF-2: No. 833 preserved, remainder scrapped
FEF-3: Nos. 844 and 838 preserved, remainder scrapped
DispositionFEF-1: No. 814 on display
FEF-2: No. 833 on display
FEF-3: No. 844 operational in excursion service, No. 838 in storage as source of spare parts

The 45 locomotives were the last steam locomotives built for the Union Pacific. They represented the epitome of dual-service steam locomotive development; funds and research were being concentrated into the development of diesel-electric locomotives. Designed to burn coal, they were converted to run on fuel oil in 1946.[1] They pulled a variety of passenger trains, such as the Overland Limited, Los Angeles Limited, Portland Rose and Challenger,[2] until diesel-electric locomotives took over passenger service. Many FEF Series locomotives were later reassigned to freight service during the last few years of their careers.

Four FEF Series locomotives survive today, including No. 844, which remains in operational condition and now runs in excursion service. Today, the 844 is one of the Union Pacific's oldest serving locomotives[3] and the only steam locomotive never retired by a North American Class I railroad.[4]


During the late 1930s, the rising trainloads started to exceed the limits of the 4-8-2 that were the mainstay of the UP passenger operations. One day, in 1937, with UP President William Jeffer's business car in the rear, a "7000" Class 4-8-2 demonstrated the lack of steaming power inherent in the type. Even when the train was waiting for rescue, a telegram was sent to ALCO in Schenectady seeking something better. The result was a superb class of 45 locomotives that could run at 100 mph and produce between 4,000 and 5,000 drawbar horsepower. They also ran about 14,000 miles a month.[5]


The FEF Series consisted of three classes of steam locomotives: FEF-1, FEF-2, and FEF-3.

Table of orders and numbers
Class Quantity Manufacturer Alco



Serial Nos. Year built UP No. Notes
FEF-1 20 American Locomotive Company S-1769 68808-68827 1937 800–819 Converted to oil fuel in 1945-1946.
FEF-2 15 American Locomotive Company S-1811 69161-69175 1939 820–834 Converted to oil fuel in 1945-1946.
FEF-3 10 American Locomotive Company S-1937 72782-72791 1944 835–844 Converted to oil fuel in 1945-1946. No. 844 in excursion service since 1960; renumbered to 8444 from 1962 to 1989.


The first twenty locomotives, numbered 800–819, were delivered by ALCO in 1937. The "800"s as a whole followed – like Northumbrian 108 years earlier – the simplest possible arrangement of only having two outside cylinders. Fitting ALCO's lateral motion devices to the leading coupled wheels eased the negotiation of curves. Complicated accessories often spoiled the basic simplicity of so many US locomotives, but UP resisted most of them, resulting in an elegant, uncluttered appearance. Despite frequently moving at speeds over 100 mph (161 km/h), the forces and stresses on the coupling and connecting rods were kept within acceptable limits. There were thus excellent results, and there were many reports[by whom?] of the class reaching the design limit of 110 mph (177 km/h).


The second batch of fifteen was delivered in 1939. These had several improvements, including larger cylinders, better tractive effort, taller driving wheels, and smoke deflectors on the sides of the smokebox. The greatest change, however, was the provision of a fourteen wheeled "pedestal" or "centipede" tender, in place of the twelve wheeled ones of the first twenty locomotives. Thus, the first locomotives became known as "FEF-1," while these were known as "FEF-2."


Except for the use of some substitute materials, the final batch of ten were nearly identical to the FEF-2. After World War II, coal supplies were affected by a series of strikes. In order to safeguard operations, UP converted the 800s to oil burning, and a 6,000 US gallons (23,000 l; 5,000 imp gal) tank was fitted in the bunker space. Otherwise, few modifications were needed to ensure years of mainline service. These were the last steam locomotives delivered for the UP. Like many of the "late era" steam locomotives, their final design was cut short by the advent of diesel locomotives, the new monarchs of the rails. A former manager of the Union Pacific Steam Program once commented on the FEF series, saying that "although it is stated that the UP FEF Series were designed to safely operate at 120 mph (190 km/h), no one really knows how fast the final 4-8-4 could go, the last FEF-3 was actually never retired."

Surviving examplesEdit

Four FEF Series locomotives survive. Two, No. 814 (FEF-1) and No. 833 (FEF-2), are on static display. A third, No. 844 (FEF-3), has remained operational and is currently used in excursion service. There is also a fourth locomotive, No. 838 (FEF-3); however it is solely used as a source of spare parts for No. 844.

Surviving FEF locomotives[6]
Type Number Image Date built Serial number Location Coordinates Notes
FEF-1 814   September 1937 68822 RailsWest Railroad Museum, Council Bluffs, Iowa 41°14′52″N 95°51′10″W / 41.24778°N 95.85278°W / 41.24778; -95.85278 (FEF-1 814)
FEF-2 833   October 1939 69174 Utah State Railroad Museum, Ogden, Utah 41°13′15″N 111°58′47″W / 41.22083°N 111.97972°W / 41.22083; -111.97972 (FEF-2 833) Originally on display at Pioneer Park in Salt Lake City, Utah.
FEF-3 838   December 1944 72785 Union Pacific Railroad, Cheyenne, Wyoming 41°7′46.9308″N 104°48′49.1688″W / 41.129703000°N 104.813658000°W / 41.129703000; -104.813658000 (FEF-3 838) Source of spare parts for 844.
FEF-3 844   December 1944 72791 Union Pacific Railroad, Cheyenne, Wyoming 41°7′46.9308″N 104°48′49.1688″W / 41.129703000°N 104.813658000°W / 41.129703000; -104.813658000 (FEF-3 838) The only steam locomotive never retired by a North American Class I railroad.[7]

See alsoEdit


  1. ^ "Union Pacific 4-8-4 "Northern" Locomotives in the USA". www.steamlocomotive.com. Retrieved 2019-06-05.
  2. ^ See Edmonson, Harold A. and Goodheart, David. "Union Pacific's 8444," at 1 (1989, Goodheart Publications).
  3. ^ Klein, Maury (2011). Union Pacific: The Reconfiguration: America's Greatest Railroad from 1969 to the Present. New York: Oxford University Press. p. 163.
  4. ^ Union Pacific Railroad (2012). "Living Legend No. 844". UP.com. Retrieved February 16, 2014.
  5. ^ https://steamlocomotive.com/locobase.php?country=USA&wheel=4-8-4&railroad=up
  6. ^ http://utahrails.net/up-steam-roster/up05-1915-1962-04.php
  7. ^ UP historical locomotives Archived September 6, 2011, at the Wayback Machine

Further readingEdit

  • Bush, John E. (2013). Building Union Pacific 844: The Birth of the FEF-3 Steam Class (1st ed.). South Platte Press. ISBN 978-0-942035-98-8.
  • Kratville, William W. (1967). The Mighty 800 (1st ed.). Kratville Publications. ASIN B0007EME4Y.