Union Pacific FEF Series 4-8-4 Steam Locomotive
The FEF was a series of three steam locomotive types owned and operated by the Union Pacific Railroad. The classes were: FEF-1; FEF-2; FEF-3. "FEF" was an acronym for the wheel arrangement, "four-eight-four."

During the late 1930s, the rising trainloads started to exceed the limits of the then in use 4-8-2's, which 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, dialog by telegram was sent to Alco in Schenectady, with a view of something better. The result was a superb class of forty-five locomotives.

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 of 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 insure years of mainline service. These were the last steam locomotives delivered for the UP. 844, the last of the FEF-3 class, is the longest continuously operating 4-8-4 engine in the world, and the only one never retired by a Class I railroad. Like many of the "late era" steam locomotives, their final design was cut short by the advent of new monarchs of the rails, diesels. "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" (Steve A. Lee, Manager of Union Pacific Steam Program, Retired).

Surviving examples

Number: 814

Type: FEF-1
Owner: Rock Island Railroad Museum
Location: Council Bluffs, Iowa
Current Status: Display

Number: 833

Type: FEF-2
Owner: Utah State Railroad Museum
Location: Union Station, Ogden, Utah
Current Status: Display

Number: 838

Type: FEF-3
Owner: Union Pacific Railroad
Location: Union Pacific Steam Shop, Cheyenne, Wyoming
Current Status: Stored
Notes: Source of spare parts for 844.

Number: 844

Type: FEF-3 
Owner: Union Pacific Railroad
Location: Union Pacific Steam Shop, Cheyenne, Wyoming
Current Status: Operational
Notes: The only steam locomotive never retired by a North American Class I railroad.

Union Pacific FEF Series Overview
Type and origin
Power type: Steam
Builder: American Locomotive Company
Build date: 1937–1944
​ • Whyte 4-8-4
 • UIC 2′D2′ h2
Gauge: 4 ft 8 1⁄2 in (1,435 mm)
Driver diameter: FEF-1: 77 in (1,956 mm)
Driver diameter: FEF-2/3: 80 in (2,032 mm)
Wheelbase Locomotive and tender: 98 ft 5 in (30.00 m)
Adhesive weight: FEF-1: 270,000 lb (122.5 tonnes)
Adhesive weight: FEF-2/3: 266,500 lb (120.9 tonnes)
Locomotive weight: FEF-1: 465,000 lb (210.9 tonnes)
Locomotive weight: FEF-2/3: 483,000 lb (219.1 tonnes)
Total weight: FEF-1: 830,150 lb (376.5 tonnes)
Total weight: FEF-2/3: 908,000 lb (411.9 tonnes)
Fuel type: Coal (No. 5 fuel oil on FEF-3)
Fuel capacity Coal: 50,000 lb (22.7 tonnes),
Fuel capacity Oil: 6,000 US gal (22,712.5 litres; 4,996.0 imperial gallons)
Water capacity: 20,000 US gal (76,000 l; 17,000 imp gal)
 • Firegrate area 100 sq ft (9.3 m2)
Boiler: 86  3⁄16 in (2189.2 mm) diameter
Boiler pressure: 300 lbf/in2 (2.07 MPa)
Heating surface: 4,224 sq ft (392.4 m2)
 • Tubes 2,204 sq ft (204.8 m2)
 • Flues 1,578 sq ft (146.6 m2)
 • Firebox 442 sq ft (41.1 m2)
​ • Heating area 1,400 sq ft (130 m2)
Cylinders: Two
Cylinder size FEF-1: 24.5 in × 32 in (622 mm × 813 mm)
Cylinder size FEF-2/3: 25 in × 32 in (635 mm × 813 mm)
Performance figures
Tractive effort FEF-1: 66,610 lbf (296.3 kN)
Tractive effort FEF-2/3: 66,750 lbf (296.9 kN)
Factor of adhesion FEF-1: 4.24
Factor of adhesion FEF-2/3: 4.18
Operator: Union Pacific
Class: FEF-1, FEF-2, and FEF-3
Numbers FEF-1: 800–819
Numbers FEF-2: 820–834
Numbers FEF-3: 835–844
Delivered FEF-1: 1937
Delivered FEF-2: 1939
Delivered FEF-3: 1944
Disposition FEF-1: one preserved, remainder scrapped.
Disposition FEF-2: one preserved, remainder scrapped.
Disposition FEF-3: one in excursion service, two preserved, remainder scrapped.

See also:

4-8-4 Northern Locomotive

Steam Locomotives

Union Pacific Challenger

Union Pacific Big Boy

Union Pacific

American Locomotive Company

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Union Pacific No. 844 has just arrived at Kansas City's Union Station, March 2010.  Photo by John Cornett.

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Union Pacific No. 844 has just arrived at Kansas City's Union Station, March 2010. Photo by John Cornett.
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