The Union Pacific Big Boy is a type of simple
articulated
An articulated vehicle is a vehicle which has a permanent or semi-permanent pivot joint in its construction, allowing it to turn more sharply. There are many kinds, from heavy equipment to buses, trams and trains. Steam locomotives were sometim ...
4-8-8-4 steam locomotive
A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...
manufactured by the
American Locomotive Company
The American Locomotive Company (often shortened to ALCO, ALCo or Alco) was an American manufacturer of locomotives, diesel generators, steel, and tanks that operated from 1901 to 1969. The company was formed by the merger of seven smaller locomo ...
(ALCO) between 1941 and 1944 and operated by the
Union Pacific Railroad
The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...
in revenue service until 1962.
The 25 Big Boy locomotives were built to haul
freight
Cargo consists of bulk goods conveyed by water, air, or land. In economics, freight is cargo that is transported at a freight rate for commercial gain. ''Cargo'' was originally a shipload but now covers all types of freight, including transp ...
over the
Wasatch Range
The Wasatch Range ( ) or Wasatch Mountains is a mountain range in the western United States that runs about from the Utah-Idaho border south to central Utah. It is the western edge of the greater Rocky Mountains, and the eastern edge of the G ...
between
Ogden, Utah
Ogden is a city in and the county seat of Weber County, Utah, United States, approximately east of the Great Salt Lake and north of Salt Lake City. The population was 87,321 in 2020, according to the US Census Bureau, making it Utah's eighth ...
, and
Green River, Wyoming
Green River is a city in and the county seat of Sweetwater County, Wyoming, United States, in the southwestern part of the state. The population was 12,515 at the 2010 census.
History
The townsite of Green River, Dakota Territory was platted ...
. In the late 1940s, they were reassigned to
Cheyenne, Wyoming
Cheyenne ( or ) is the capital and most populous city of the U.S. state of Wyoming, as well as the county seat of Laramie County, with 65,132 residents, per the 2020 US Census. It is the principal city of the Cheyenne metropolitan statistical ...
, where they hauled freight over
Sherman Hill to
Laramie, Wyoming
Laramie is a city in and the county seat of Albany County, Wyoming, United States. The population was estimated 32,711 in 2019, making it the third-largest city in Wyoming after Cheyenne and Casper. Located on the Laramie River in southeastern ...
. They were the only locomotives to use a 4-8-8-4
wheel arrangement
In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...
: four-wheel leading truck for stability entering curves, two sets of eight driving wheels and a four-wheel trailing truck to support the large
firebox
Firebox may refer to:
*Firebox (steam engine), the area where the fuel is burned in a steam engine
*Firebox (architecture), the part of a fireplace where fuel is combusted
*Firebox Records
Firebox Records was a Finnish record label based in S ...
.
Today, eight Big Boys survive, with most on static display at museums across the USA. One of them,
No. 4014, was re-acquired by Union Pacific, and between 2014 to 2019 it was rebuilt to operating condition for the 150th anniversary of the
first transcontinental railroad
North America's first transcontinental railroad (known originally as the "Pacific Railroad" and later as the " Overland Route") was a continuous railroad line constructed between 1863 and 1869 that connected the existing eastern U.S. rail netwo ...
. It thus regained the title as the largest and most powerful operating steam locomotive in the world.
History
Design
In 1936, Union Pacific introduced the
Challenger-type (
4-6-6-4) locomotives on its
main line
Mainline, ''Main line'', or ''Main Line'' may refer to:
Transportation
Railway
* Main line (railway), the principal artery of a railway system
* Main line railway preservation, the practice of operating preserved trains on an operational railw ...
over the Wasatch Range between Green River and Ogden.
For most of the route, the maximum
grade
Grade most commonly refers to:
* Grade (education), a measurement of a student's performance
* Grade, the number of the year a student has reached in a given educational stage
* Grade (slope), the steepness of a slope
Grade or grading may also ref ...
is 0.82% in either direction, but the climb eastward from Ogden, into the Wasatch Range, reached 1.14%.
Hauling a freight train demanded
double heading
In railroad terminology, double heading indicates the use of two locomotives at the front of a train, each operated individually by its own crew. The practice of triple-heading involves the use of three locomotives. The practice of multi-headi ...
and helper operations, which slowed service.
So Union Pacific decided to design a new locomotive that could handle the run by itself:
faster and more powerful than the compound
2-8-8-0s that UP tried after
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, able to pull long trains at a sustained speed of once past mountain grades.
A Union Pacific design team led by Otto Jabelmann, the head of the Research and Mechanical Standards section of the Union Pacific's Mechanical Department, worked with ALCO (the American Locomotive Company) to re-examine their Challenger locomotives.
The team found that the railroad's goals could be achieved by enlarging the Challenger firebox to about (about ), increasing boiler pressure to 300 psi, adding four driving wheels, and reducing the size of the driving wheels from .
The new locomotive was carefully designed not to exceed an axle loading of , and achieved the maximum possible starting tractive effort with a
factor of adhesion
An adhesion railway relies on adhesion traction to move the train. Adhesion traction is the friction between the drive wheels and the steel rail. The term "adhesion railway" is used only when it is necessary to distinguish adhesion railways from ...
of 4.0.
It was designed to travel smoothly and safely at 80 miles per hour.
To achieve these new engineering goals, the Challenger locomotive was "comprehensively redesigned from first principles," wrote locomotive historian Tom Morrison.
The overall design simplified some aspects of previous locomotive designs and added complexity elsewhere. Compounding, booster, and feed water heaters were eliminated, as were
Baker valve gear After about 1910, the Baker valve gear was the main competitor to Walschaerts valve gear for steam locomotives in the United States. Strictly speaking it was not a valve gear but a variable expansion mechanism adapted to the Walschaerts layout repl ...
and limited cut-off. But the "proliferation of valves and gauges on the backhead showed that running a Big Boy was an altogether more complicated and demanding task for the crew than running previous existing locomotives," Morrison wrote.
![Union Pacific Big Boy 4000 1941](https://upload.wikimedia.org/wikipedia/commons/3/35/Union_Pacific_Big_Boy_4000_1941.JPG)
The 4-8-8-4 class series, originally rumored to be called the "Wasatch", after the Wasatch Mountains, acquired its nickname after an unknown ALCO worker scrawled "Big Boy" in chalk on the front of No. 4000's
smokebox
A smokebox is one of the major basic parts of a steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is e ...
door, then under construction as the first of its class.
The Big Boys were articulated, like the
Mallet locomotive
The Mallet locomotive is a type of articulated steam railway locomotive, invented by the Swiss engineer Anatole Mallet (1837–1919).
The front of the locomotive articulated on a bogie. The compound steam system fed steam at boiler pressur ...
design, though lacking the compounding of the Mallet. They were built with a wide margin of reliability and safety, and normally operated well below in freight service. Peak drawbar horsepower was reached at about .
The maximum drawbar pull measured during 1943 tests was while starting a train.
The Big Boy has the longest engine body of any reciprocating steam locomotive, longer than two 40-foot buses.
They were also the heaviest reciprocating steam locomotives ever built, the combined weight of the engine and tender outweighed a
Boeing 747
The Boeing 747 is a large, long-range wide-body airliner designed and manufactured by Boeing Commercial Airplanes in the United States between 1968 and 2022.
After introducing the 707 in October 1958, Pan Am wanted a jet times its size, t ...
.
There was some speculation that the first series of
Chesapeake and Ohio 2-6-6-6 “Allegheny” locomotives, built by the
Lima Locomotive Works
Lima Locomotive Works was an American firm that manufactured railroad locomotives from the 1870s through the 1950s. The company took the most distinctive part of its name from its main shop's location in Lima, Ohio. The shops were located between ...
in 1941, may have weighed as much as , exceeding the Big Boys, but subsequent re-weighs of early-production H8s, under close scrutiny by the builder and the railroad, found them to be less than .
Construction
The American Locomotive Company manufactured 25 Big Boy locomotives for Union Pacific: 20 in 1941 and five in 1944.
Along with the Challengers, the Big Boys arrived on the scene just as traffic was surging in preparation for American participation in
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
.
Operation
![4017 Backhead 20040426](https://upload.wikimedia.org/wikipedia/commons/c/c5/4017_Backhead_20040426.jpg)
The Big Boy locomotives had large grates to burn the low-quality
bituminous coal
Bituminous coal, or black coal, is a type of coal containing a tar-like substance called bitumen or asphalt. Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams. It ...
supplied by Union Pacific-owned mines in Wyoming. Coal was carried from the tender to the firebox by a Standard Stoker Company type MB
automatic stoker capable of supplying slightly over per hour. Water was injected into the boiler by a Nathan type 4000C Automatic Restarting
injector
An injector is a system of ducting and nozzles used to direct the flow of a high-pressure fluid in such a way that a lower pressure fluid is entrained in the jet and carried through a duct to a region of higher pressure. It is a fluid-dynamic ...
(up to 12,500 gallons per hour) on the right side and an Elesco T.P. 502
exhaust steam injector (up to 14,050 gallons per hour) on the left side. A Big Boy could consume 11 tons of coal and 12,000 gallons of water an hour operating at maximum power.
As an experiment, No. 4005 was converted to burn oil in 1946.
Unlike a similar effort with the Challengers, the conversion failed due to uneven heating in the Big Boy's large, single-burner firebox.
The locomotive was converted back to coal in 1948.
(Decades later, No. 4014 would be successfully converted to oil during its restoration.
) Another experiment saw No. 4007 being modified with a single stack in October 1948. The results were unsatisfactory, and the locomotive was reverted back to double stack after testing.
One final short-term experiment was the fitting of
smoke deflectors
Smoke deflectors, sometimes called "blinkers" in the UK because of their strong resemblance to the blinkers used on horses, and "elephant ears" in US railway slang, are vertical plates attached to each side of the smokebox at the front of a ste ...
on locomotive 4019, similar to those found on the railroad's
FEF Series, as well as some of their Challengers. These were later removed, as the Big Boys' nozzle and blower in the smoke box could blow smoke high enough to keep engineers’ lines of sight clear.
![Union Pacific X4014 (49097041782)](https://upload.wikimedia.org/wikipedia/commons/8/87/Union_Pacific_X4014_%2849097041782%29.jpg)
The locomotives were held in high regard by crews, who found them sure-footed and more “user friendly” than other motive power. They were capable machines, and their rated hauling tonnage was increased several times over the years. But postwar increases in the price of coal and labor, along with the advent of efficient, cost-effective
diesel-electric power, spelled the end of their operational lives. Nonetheless, they were among the last steam locomotives withdrawn from service on the Union Pacific. The last revenue train hauled by a Big Boy ended its run early in the morning on July 21, 1959. Most were stored operational until 1961; four remained in operational condition at
Green River, Wyoming
Green River is a city in and the county seat of Sweetwater County, Wyoming, United States, in the southwestern part of the state. The population was 12,515 at the 2010 census.
History
The townsite of Green River, Dakota Territory was platted ...
until 1962. Their duties were assumed by
diesel locomotive
A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving whee ...
s and
gas turbine-electric locomotives.
In 2019, Union Pacific completed the restoration of No. 4014 and placed it in
excursion service
A heritage railway or heritage railroad (US usage) is a railway operated as living history to re-create or preserve railway scenes of the past. Heritage railways are often old railway lines preserved in a state depicting a period (or periods) i ...
. The locomotive was sent on a tour in celebration of the 150th anniversary of the completion of the
First transcontinental railroad
North America's first transcontinental railroad (known originally as the "Pacific Railroad" and later as the " Overland Route") was a continuous railroad line constructed between 1863 and 1869 that connected the existing eastern U.S. rail netwo ...
.
Accident
On April 27, 1953, No. 4005 was pulling a freight train through southern
Wyoming
Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...
when it jumped a switch track at , throwing the engine onto its left side and derailing its tender and the first 18 freight cars of its 62-car train. The engineer and fireman were killed on impact; the brakeman died of severe burns in a hospital a few days later. The tender destroyed the cab of the locomotive, and the loads from the 18 derailed cars were scattered. The locomotive was repaired by Union Pacific at its Cheyenne facility and returned to service until 1962.
Preservation
Most of the 25 Big Boys were scrapped, but seven remain on static display—two indoors and five outdoors, under the elements—and an eighth,
Union Pacific 4014, was rebuilt to operating condition by Union Pacific's steam program.
See also
*
Union Pacific Challenger
The Union Pacific Challengers are a type of simple articulated 4-6-6-4 steam locomotive built by American Locomotive Company (ALCO) from 1936 to 1944 and operated by the Union Pacific Railroad until the late 1950s.
A total of 105 Challengers wer ...
*
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.
The 45 locomotives were t ...
*
Union Pacific Heritage Fleet
The Union Pacific Heritage Fleet includes commemorative and historic equipment owned by the Union Pacific Railroad. The fleet currently consists two historic steam locomotives, three historic diesel locomotives, seventeen modern diesel locomoti ...
*
EAR 59 class – The world's largest metre-gauge steam locomotive, operated by East African Railways
Notes and references
Citations
References
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Further reading
*
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External links
UP Steam
{{Authority control
4-8-8-4 locomotives
4000
ALCO locomotives
Simple articulated locomotives
Railway locomotives introduced in 1941
Steam locomotives of the United States
Freight locomotives
Standard gauge locomotives of the United States