🚂Railhub
ShortlistInquiriesJobs

Facilities

  • All Facilities
  • Facility Map
  • Transload
  • Rail-Served Properties
  • Browse Geography
  • Open facilities

Providers & Services

  • Providers & Services
  • Software & Data Vendors
  • Open providers

Railroads & Network

  • Railroads
  • Short Line Directory
  • Intermodal
  • Bridges
  • Crossings
  • Open railroads

Market & Ops Data

  • Industry Overview
  • Service Performance
  • Fuel Surcharges
  • Safety
  • Regulatory
  • Open data

Reference & Resources

  • Resources Hub
  • Glossary
  • Reporting Marks
  • Commodity Codes
  • Organizations
  • Cross-Border
  • Open resources

Utility

  • Shortlist
  • Inquiries
  • Jobs
  • Full-time
  • Remote
  • Operations

© 2026 Railhub. All rights reserved.

  1. Home
  2. /
  3. Resources
  4. /
  5. Glossary
  6. /
  7. Association of American Railroads
Regulatory

Association of American Railroads(AAR)

Definition

The principal trade and standard-setting organization for the major freight and passenger railroads in North America. The AAR develops and publishes interchange rules, equipment standards, safety standards, and technical specifications that govern how railroads interact with each other. Membership includes Class I railroads, Amtrak, and many regional and short line railroads.

Related Terms

Surface Transportation Board(STB)

The independent U.S. federal agency responsible for the economic regulation of the nation's freight railroads, including jurisdiction over rates, mergers, acquisitions, line sales, and abandonments. The STB was created by the ICC Termination Act of 1995 as the successor to the Interstate Commerce Commission. It adjudicates shipper complaints about unreasonable rates and competitive access.

Federal Railroad Administration(FRA)

The U.S. Department of Transportation agency responsible for railroad safety regulation and enforcement, including track standards, equipment inspection, operating rules, and hazardous materials transportation. The FRA conducts safety inspections, investigates accidents, and issues emergency orders when immediate safety threats exist. It also administers federal rail investment programs.

Interchange

The transfer of freight cars and the accompanying waybills between two connecting railroads at a junction point. Interchange rules, governed by AAR circulars, define responsibilities for car condition, billing, and liability. It is the mechanism that enables single-bill, multi-railroad shipments across the North American network.

Car Hire

A compensation system under which a railroad pays a daily or mileage-based fee to the car owner when using foreign-owned or privately owned equipment. Car hire rates are established under AAR rules and are intended to recover the owner's fixed and variable car costs. The system balances car supply across the national rail network.

Railinc

The AAR-affiliated technology company that provides information technology services and data standards for the North American rail industry, including the UMLER equipment registry, the Centralized Station Master location database, Jettison EDI translation, and the car location network. Railinc is the central data utility connecting railroads, shippers, and service providers. It maintains the authoritative registry of rail equipment and industry codes.

More in Regulatory

CircularClass I RailroadCommon Carrier ObligationCompetitive Access RulePipeline and Hazardous Materials Safety AdministrationShipper Complaint