This X12 Transaction Set contains the format and establishes the data contents of the Railroad Equipment Inquiry or Advice Transaction Set (456) for use within the context of an Electronic Data Interchange (EDI) environment. The transaction set can be used in the following ways: (1) for a provider of equipment or transportation service to provide information to a qualified customer; (2) for a qualified customer to inquire as to the location of equipment or shipments; and (3) for one company to provide another company with equipment or shipment information.