9.0.3 Rolling Stock - AAR Mechanical Designations

Prototype Information

The American Railway Association (ARA), the predecessor of the Association of American Railroads (AAR) established a system of mechanical designations of freight cars to describe their suitability for transport of different cargoes. 

This standardized system, when added to specific car's dimensional data found in Official Railway Equipment Registers of the period, allows railroads to quickly identify a car's dimensions, loading mechanisms, and capacity for safe interchange, billing, and routing.

The designation consists of a 2-to-4 character alphanumeric code that tells railroad personnel exactly what kind of equipment they are handling without needing to physically inspect the railcar. Additional letters or digits define the specific features of the car, such as loading/unloading mechanisms, special flooring, or refrigeration.

AAR Mechanical Designations as they apply to the WWSL located in three files: 

9.0.3.1 Passenger Cars 

• PASSENGER
• DINER CARS 
  
• BAGGAGE  
• POSTAL CARS

9.0.3.2 Freight Car

BOX CARS

CABOOSE

FLAT CARS

TOFC HISTORY

GONDOLAS

HOPPERS

MOTORCARS

REFRIGERATOR

STOCK CARS

TANK CARS

 9.0.3.3 Maintenance of Way 

• MOW EQ'PT. 

 The WWSL

 

The WWSL uses the AAR mechanical designations as part of the WWSL Car Movement Program.