Interchange

Interchange is the transfer of railcars from one railroad to another so that a single shipment can move over the tracks of more than one carrier. Because no railroad reaches every shipper and consignee, most carloads travel over the lines of two or more roads, handed off from one to the next until they reach their destination. This handoff is the core mechanism that ties the individual railroads of North America into a single connected freight network.

How It Works

A car is interchanged at an agreed interchange point, where the delivering road sets the car out and the receiving road takes it into its own train. Ownership of the lading does not change, but responsibility for the car and its safe movement passes to the receiving road. The receiving road may inspect the car before accepting it and can refuse a car found with a defect - a rejection at interchange.

Interchange usually involves only the cars: the delivering road's locomotives and crew normally come off at the interchange point, and the receiving road supplies its own power and crew to move the cars onward. In some cases, though, railroads run the train straight through - the delivering road's locomotives stay on the train and the receiving road's crew simply boards and continues. These run-through arrangements are used for operational efficiency, sparing the time and effort of swapping power and re-marshaling the train at the handoff.

Rules and Accounting

Interchange between freight railroads is governed by the interchange rules published by the AAR, which define what condition a car must be in to be accepted, who is responsible for repairs, and how those repairs are billed back to the car owner through Car Repair Billing. The same framework standardizes reporting marks, car registration, and equipment data so that any car can move smoothly across the network regardless of which road owns it.