How SCAC Codes Are Assigned

To learn more about how codes are assigned, see the following: 

• Understanding SCAC Application Code Rules
• Rules for Code Suggestions
• Reporting Marks
• Using Codes Reserved for Identifying Equipment (Ending in U, X, or Z)
• Using Codes Ending in U
• Using Codes Ending in X
• Using Codes Ending in Z

Understanding SCAC Application Code Rules

The SCAC application automatically assigns codes based on the following rules:

• Codes are four letters, with the following exception: Railroads and passenger motor carrier companies are assigned two-, three-, or four-letter codes. 
• Codes are assigned based on the company's name. If the company has a legal name and a “doing business as” (DBA) name, then the SCAC is assigned based on the DBA name.
• Codes are selected from the initials of the company name. If any of the initials/letters are not available, the code can contain any combination of letters.
• Containers, private railcars, and intermodal chassis and trailers are assigned codes ending with the letter U, X, or Z. See Codes Ending in U, X, or Z for more information.

Rules for Code Suggestions

The SCAC system uses the following rules to generate code suggestions. If the system cannot find any available codes, then the system suggests codes based on any available letter combination.

• The first letter of the code is the initial of the first word in the company name. For example, if the first letter of the first word of the company name is A, then the first letter of the code is A.
• The next letters are the initials of the remaining words in the company name.
• If the combination of initials creates a code already assigned, then other letters from the words in the company name are used to create a unique code.
• Initials can be repeated.
• If the first word of the company name is “the”, then the first initial is based on the second word in the name. Note that this rule is for English names only. For French or Spanish names, if the name starts with words such as “Le”, “Les”, “La”, “Las”, or “Los”, then the first initial of the codes is based on that specific word.
• If the company name contains punctuation, such as commas, periods, or apostrophes, this punctuation is ignored and does not impact the code creation.

Reporting Marks

A SCAC assigned to equipment moving on the railroads is called a reporting mark. Reporting marks may be two-, three-, or four-letters and are stenciled on the equipment along with a 6-digit unit number that is assigned by the owner of the equipment.

In addition, railroads that are connected to the North American railroad system are assigned two-, three-, or four-letter reporting marks (or marks) that may not end with the letters U, X, or Z. These reporting marks that end in a letter other than U, X, or Z are assigned to common carrier railroads for use on railroad equipment in interchange service. 

Reporting marks are assigned by Railinc in cooperation with NMFTA by using the SCAC application, ensuring that codes are not duplicated. Codes can also be reserved in the SCAC application until such a time that they are officially assigned by Railinc to the railroad. A company cannot run its private equipment on the North American Railroad system without having a reporting mark.

Using Codes Reserved for Identifying Equipment (Ending in U, X, or Z)

Certain SCACs are set aside for the identification of specific types of equipment, such as containers, non-railroad owned railroad cars, and intermodal chassis and trailers. These codes are stenciled on transportation equipment.

The following SCACs are reserved for identifying equipment:

SCACs ending in U, X, or Z can be assigned to applications or reserved and assigned/activated using the Manage Reservations feature.

Using Codes Ending in U

These codes are for domestic and international container-owning companies. If necessary, NMFTA can assign these codes for domestic containers (equipment moving only in North America). The Bureau International des Containers et du Transportation assigns U ending codes for containers moving in international commerce (containers that move into North America from other continents).

Companies may have multiple codes per container. This rarely happens with domestic container operators, but it does happen more frequently with the international operators. International equipment owners may use one SCAC to identify up to 999,999 containers, or they can use more codes if they prefer. If containers are sold, it may be impractical for the new owner to have them stenciled with a new code. Thus, NMFTA and BIC do not require reassignment of the code to make it match the new company’s name. If we receive notice that the code was assigned to a different company, simply update our records.

Using Codes Ending in X

These codes can only be assigned to private rail car companies. NMFTA does not assign those codes. Responsibility for maintenance has been delegated to the Association of American Railroads and run through Railinc.

If a company has its own railroad car, whether it's a freight car or passenger car, they must go to Railinc to get a reporting mark.

Using Codes Ending in Z

These codes can only be assigned to intermodal chassis and trailer companies. NMFTA does not assign those codes. Responsibility for maintenance has been delegated to the Association of American Railroads and run through Railinc.

A container sits on a chassis/trailer. Intermodal chassis and trailers get a reporting mark ending with the letter Z to be able to be moved by the railroad.

All content © Copyright 2025 National Motor Freight Traffic Association, Inc.™ All Rights Reserved.