AAR

E20202

AAR is the American Association of Railroads' wheel arrangement classification system commonly used to describe locomotive axle configurations in North America.

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Statements (37)

Predicate Object
instanceOf locomotive axle configuration notation
wheel arrangement classification system
basedOn count of powered and unpowered axles in each truck
classificationGranularity axle-level rather than wheel-level
comparedWith UIC wheel arrangement classification
Whyte notation
domain locomotive design
railway engineering
exampleNotation A1A-A1A
B-1-B
B-B
B-B-B
C-C
fullName American Association of Railroads wheel arrangement classification system
hasConcept powered axle
truck (bogie) as a grouping of axles
unpowered axle
interprets AAR self-linksurface differs
surface form: A1A-A1A means two trucks each with an outer powered axle, one idle axle, and an outer powered axle

B-1-B means two two-axle powered trucks separated by a single unpowered axle
B-B means two trucks each with two powered axles
C-C means two trucks each with three powered axles
notationFeature uses hyphens to separate trucks or groups of axles
uses letters to denote powered axles
uses numbers to denote unpowered axles
notUsedFor detailed steam locomotive wheel arrangements
primaryUsers North American rail network
surface form: North American freight railroads

North American rail network
surface form: North American passenger railroads
relatedTo Association of American Railroads
scope multiple-unit rail vehicles
primarily diesel and electric locomotives
standardizedBy Association of American Railroads
usedBy locomotive manufacturers
railroad industry
railroad operators
usedFor classifying wheel arrangements of locomotives
describing locomotive axle configurations
usedInRegion North America

Referenced by (2)

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

AAR interprets AAR self-linksurface differs
this entity surface form: A1A-A1A means two trucks each with an outer powered axle, one idle axle, and an outer powered axle