Railroad station master file information is transmitted using this transaction set to establish and maintain records for rail facilities. Railroads or rail data service providers send 431 transactions to receiving railroads, rail management systems, or logistics partners to communicate station identification, location details, and operational capabilities. The transaction originates proactively or in response to requests for station master data updates. Key segments include the SMB (Beginning Segment for Railroad Station Master File), which opens the transmission and establishes context; the SMS (Station Codes Segment), which provides unique identifiers and classification codes for the station; and the N4 (Geographic Location) segment, which specifies the station’s physical location using city, state, postal code, and country information.

For example, Union Pacific Railroad transmits a 431 transaction to BNSF Railway containing updated master file information for their Kansas City intermodal terminal. The SMB segment identifies this as a station master file update, the SMS segment supplies the facility code and station type classification, and the N4 segment confirms the geographic coordinates as Kansas City, Kansas. The optional SMA (Station Address) segments provide the terminal’s street address and contact information, while SMO (Operational Services) segments detail which services—such as container handling or hazmat processing—are available at that location. This allows BNSF to maintain current, accurate records of Union Pacific’s station capabilities in their system without requiring manual data entry or separate coordination calls.