Rail carriers use the 423 transaction set to communicate industrial switch lists—detailed instructions for positioning and pulling railroad cars at customer facilities. A railroad or switching service sends this document to the receiving facility (shipper, consignee, or industrial customer) to specify which cars must be placed or removed and when. The transaction set relies on the DTM (Date/Time Reference) segment to indicate scheduling details, the N1 and N3 (Name and Address Information) segments to identify the facility and parties involved, and the LX (Assigned Number) segment to organize multiple switching operations within a single list. Within each LX loop, the N7 (Equipment Details) segment identifies specific rail cars, while XD (Placement/Pull Data) segments define the actual positioning instructions for each car.

A regional switching company receives instructions from BNSF Railway to manage operations at a chemical manufacturer’s rail siding. The switch list details that on March 15th at 0800 hours, three tank cars must be pulled from the customer’s facility (identified through the N7 segments), with one car destined for a distribution center in Memphis and two cars returning to a loading facility in Houston (specified via the D9 and F9 destination and origin station segments). If any of these cars contain hazardous materials, the LH1 loop provides classification details, shipping names through LH3, and compliance references through LEP for EPA requirements. The receiving customer’s operations manager uses this structured information to coordinate staff, position equipment, and prepare cars for pickup at the specified time.