Union Pacific Big Boy class locomotives

E493346

The Union Pacific Big Boy class locomotives were massive 4-8-8-4 articulated steam engines built for Union Pacific Railroad, famed as some of the largest and most powerful steam locomotives ever constructed.

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Statements (59)

Predicate Object
instanceOf articulated locomotive class
steam locomotive class
4014RestorationCompletionYear 2019
boilerPressure 300 psi
builder ALCO Schenectady Works
American Locomotive Company
classDesignation UP class 4000
configurationType Whyte notation 4-8-8-4
countryOfOrigin United States
cylinderArrangement simple articulated
cylinderCount 4
cylinderSize 23.75 in × 32 in
designedFor long, heavy freight trains
steep grades
designer Otto Jabelmann
Union Pacific Railroad mechanical department
driverDiameter 68 inches
engineWeight about 772,000 lb
factorOfAdhesion about 4.0
firstRunYear 1941
fuelCapacity approximately 28 tons of coal
fuelType coal
historicalEra World War II era
transition era from steam to diesel
lengthOverCouplers about 132 feet
maximumSpeed approximately 80 mph
nickname Big Boy
notableFor being among the largest steam locomotives ever built
being among the most powerful steam locomotives ever built
numberSeries 4000–4024
operationalUnit Union Pacific 4014
operator Union Pacific Railroad
powerType steam
preservedUnitsLocation Cheyenne, Wyoming
linked to: Cheyenne

Dallas, Texas
Denver, Colorado
Green Bay, Wisconsin
Omaha, Nebraska
Pomona, California
Scranton, Pennsylvania
St. Louis, Missouri
primaryRoute Ogden, Utah – Green River, Wyoming
linked to: Ogden, Utah

Wasatch Range
primaryUse heavy freight service
productionEndYear 1944
productionStartYear 1941
railwayCompany Union Pacific Railroad
retirementPeriod 1950s
1960s
survivingUnits 8
totalLocomotiveAndTenderWeight over 1,200,000 lb
totalProduced 25
tractiveEffort approximately 135,375 lbf
typicalOperatingSpeed 35–45 mph
usedOn Overland Route
Union Pacific mainline in Wyoming and Utah
waterCapacity approximately 25,000 US gallons
weightOnDrivers about 540,000 lb
wheelArrangement 4-8-8-4

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Referenced by (2)

Full triples — surface form annotated when it differs from this entity's canonical label.

Baldwin Locomotive Works notableWork Union Pacific Big Boy class locomotives
Steamtown National Historic Site hasLocomotive Union Pacific Big Boy No. 4012
linked to: Union Pacific Big Boy class locomotives