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AAR wheel arrangement facts for kids

Kids Encyclopedia Facts

The AAR wheel arrangement is a simple way to describe how wheels are set up on locomotives. It is mainly used in North America. This system helps people understand how many wheels a train engine has and which ones are powered. It is a simpler version of another system called the UIC classification of locomotive axle arrangements.

Understanding AAR Wheel Arrangements

The AAR wheel arrangement system helps classify different types of train engines. It tells you about the wheels under the engine. It focuses on how many wheels are in each group, called a bogie or wheel assembly. It also shows which wheels are powered by the engine.

How AAR Classifies Wheels

The AAR system uses letters and numbers to describe the wheels.

  • Letters (like A, B, C) show how many powered axles are in a bogie.
    • A means one powered axle.
    • B means two powered axles.
    • C means three powered axles.
  • Numbers (like 1, 2) show how many unpowered axles are in a bogie.
  • A dash (-) separates the descriptions of different bogies.
  • A plus sign (+) means the bogies are connected in a special way.

Common AAR Wheel Arrangements

Here are some common examples of AAR wheel arrangements:

A1A-A1A Arrangement

  • This means the locomotive has two main wheel assemblies, or bogies.
  • Each bogie has three axles.
  • Out of these three axles, two are powered by the engine.
  • One axle in each bogie is not powered.
  • This setup helps the locomotive spread its weight better.

B-B Arrangement

  • This is a very common arrangement for many locomotives.
  • It means the locomotive has two bogies.
  • Each bogie has two axles.
  • All four of these axles in each bogie are powered.
  • So, a B-B locomotive has a total of eight wheels, all of which are powered.

C-C Arrangement

  • This arrangement is often found on larger, more powerful locomotives.
  • It means the locomotive has two bogies.
  • Each bogie has three axles.
  • All six of these axles in each bogie are powered.
  • This gives the locomotive a lot of pulling power.

See also

A robot friend for learning! In Spanish: Clasificación AAR para niños

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AAR wheel arrangement Facts for Kids. Kiddle Encyclopedia.