The Railway Accounting Rules (RAR) encompass the rules of the Interline Settlement System (ISS) and the Railroad Clearinghouse (RCH). The document contains general and mandatory freight rules, including overcharge and disbursement rules. It also includes arbitration procedures used to settle financial disputes among railroads, and the full Railroad Clearinghouse (RCH) settlement regulations for ISS, Car Hire Data Exchange (CHDX), Freight Loss Data Exchange (FLDX), Switching Settlement Data Exchange (SSDX) and Multi-Level Pool Billing (MLPB).

RAR is maintained by The Revenue Pipeline Task Force (RPTF). Rules are approved by the Interline Revenue Committee (IRC) and the Operations Committee.