Rail Industry Terms

AEI Tags – Automatic Equipment Identification Tags

Radio frequency devices that contain the unit’s initial and number plus other pertinent information about a piece of equipment that is affixed to each side and each end of the railcar which is read by wayside reader to allow electronic location tracking.


AAR Interchange Agreement

Contract under which subscribers agree to abide by the Code of Rules governing the equipment, condition, and repair of freight cars used in interchange service.


AAR Rule 107

Standard handling guidelines for cars that have been damaged or destroyed – used to recover the cost of the repairs or the asset, if destroyed.


AAR Signatory / Subscriber

Per Rule A.2. Of the AAR Field Manual all freight railroads, interchange freight car owners, and running repair agents must subscribe to the AAR Interchange Rules and be listed in FindUs.Rail.


Car Hire Rules

A set of rules which govern the processes and procedures for payment for the use of railroad marked freight cars and appurtenances (auto-rack superstructures) by all common carrier railroads as referenced in AAR Circular No. OT-10.


CLM - Car Location Message

A CLM is a specialized type of electronic message that is used within the rail industry to track the movements and locations of railcars. Messages are captured by wayside detectors placed along a railroads tracks and reported to Railinc. Railinc gathers the data acting like a central repository for the data.


CHARM - Car Hire Accounting Rate Master

The CHARM file is an industry file that contains all car hire rates currently in effect for each individual piece of equipment. These rates are both the default rates assigned to a car in the absence of a rate established by the agreement between the owner and user, and negotiated rates between two parties through the deprescription process of allowing car owners and car users to negotiate car hire rates for car use.


Car Service Directive/Rules

Standing directive(s) and or rules issued by the AAR that govern the assignment and user of specially equipped freight cars to specific shippers, commodity use, or general railroad agent locations. Car Service Directives are defined in AAR Circular No. OT-10.


DDCTS – Damaged and Defective Car Tracking Systems

The Damaged and Defective Car Tracking (DDCT) system automates the process for tracking, identifying, and repairing railcars through an easy-to-use, centralized web-based application. Users have real-time access to information through a single standardized source and can easily update, retrieve and share information in a timely manner.

Damaged cars are handled in accordance with AAR Interchange Rule 107, and defective cars are handled in accordance with AAR Interchange Rules 1, 96 and 108. AAR Interchange Rule 95 is used for any damaged equipment that can be returned to service.



FindUs.Rail is a web-based centralized database hosted by Railinc that enables users to review and manage their company's contact information, helping railroad departments, private car owners and leasing companies stay connected.


Mileage Equalization

In the US Mileage Equalization refers to Tank Car Mileage Equalization (TME). TME accumulates the reporting of loaded and empty private tank car mileage by Railinc. Should the empty mileage accumulated by any tank car owner exceed the loaded mileage during the same calendar year by more than six percent, such excess mileage must be paid by the tank car owner to the AAR at a rate which is determined annual. The funds are then distributed to those railroads whose handling of empty tank cars exceeded their loaded handling by more than six percent.

In Canada mileage equalization is managed by individual tariffs issued by the Canadian National and Canadian Pacific railroads. While similar to the US rules, the tariffs allow for equalization charges to be applied to all car types.


OT-5 Loading Authority

The Circular OT-5 system provides a centralized, paperless process for submitting and approving OT-5 applications. It is a web-based communication system that facilitates the potential placement of private freight equipment at specified loading location on a railroad. Rail equipment must be approved for potential loading on a rail road as specified in the Association of American Railroads Circular OT-5 for Rules Governing the Assignment of Reporting Marks, Mechanical Designations and for the Use of Private Equipment, by submitting a Circular OT-5 application to the line haul carrier for the loading location.

Additional features of the Circular OT-5 system include pre-authorization, which allows submitters to gain preliminary authorization for an OT-5 application, and a web-based interface for approving and rejecting applications.


OTMA 49-CFR 174.50 - One Time Movement Approval

Provides procedures for applying for a One-Time Movement Approval in accordance

with 49 CFR 174.50 for bulk hazardous materials packaging’s (e.g., tank cars) that do not meet the required design specification (i.e. leaking tank car) and must be moved to a cleaning facility and/or a certified repair shop to complete the necessary repairs and qualifications to bring the packaging back into compliance.


ORER - Official Railway Equipment Register

The ORER is published quarterly and contains a profile of each owner's registered fleet including details on the AAR mechanical designation, car description, dimensions, capacity and number of cars in a series. The register also contains pertinent information on car owners and agents.


RAMP-ED - Rail Asset Management Process-Exception Disposition

The RAMP-ED system enables railroads, equipment owners and leasing companies to send electronic disposition movement instructions, while recording the details of equipment movement arrangements. The system captures details of equipment move arrangements including equipment assignment initial/number pairs, reference and authorization numbers and contact information.


Reporting Mark

A Standard Carrier Alpha Code (SCAC) consisting of two to four characters used as company identifiers for railroads, and private car owners that is stenciled on owners and lessee equipment and is registered in UMER and FindUs.Rail.


UMLER – Universal Machine Language Equipment Register

The UMLER system is an industry equipment register database that contains railcar specifications required by the AAR Interchange rules for various railcar components, dimensions, carrying capacities, weight, inspection dates and many other fields.

There are over two million pieces of equipment registered in the UMLER system.


WABL – Wheels, Axles, Bearings and Lubrication

The WABL Committee's mission is to establish, improve, and maintain wheel, axle, bearing and lubrication system interchange standards and rules, and to certify and monitor the performance of new equipment.


US Department of Transportation / Secretary of Transportation Administrations

OIG = Office of Inspector General

FHA = Federal Highway Administration

FMCSA = Federal Motor Carrier Safety Administration

NHTSA = National Highway Traffic Safety Administration

SLSDC = Saint Lawrence Seaway Development Corporation

RITA = Research and Innovative Technology Administration

FAA = Federal Aviation Administration

FTA = Federal Transit Authority

FRA = Federal Railroad Administration

PHMSA = Pipeline and Hazardous Materials Safety Administration


Association of American Railroads (AAR)

SOMC = Safety and Operations Management Committee

PAMC = Policy & Advocacy Management Committee

NEMC = Network Efficiency Management Committee

TCC = Tank Car Committee

EEC = Equipment Engineering Committee

ARB = Arbitration Rules and Billing Committee