The Association of American Railroads (AAR) reported continued year-over-year growth in U.S. rail traffic for Week 28, according to a summary published by Railway Age.

AAR, the Washington, D.C.-based trade body for North America's Class I freight railroads, releases traffic data every Wednesday covering the preceding week. Its report aggregates carload and intermodal unit counts across the seven U.S. Class I systems and includes parallel figures from Mexican and Canadian carriers.

What does AAR measure each week?

The weekly summary breaks U.S. rail traffic into roughly 20 commodity groupings: coal, chemicals, grain, automotive, forest products, and metallic ores among them. Analysts, shippers, and regulators use the data to gauge shifts in industrial demand, consumer spending, and export activity.

The Surface Transportation Board (STB), the federal regulator that oversees rail rates and service, treats AAR's weekly totals as a primary industry benchmark. State departments of transportation, port authorities, and large shippers also rely on the data for short-term planning.

How intermodal fits into the report

For intermodal, AAR reports container and trailer counts separately, then combines them into a single intermodal total. Operators compare the combined figure against prior-year intermodal volumes and against truck-based freight where parallel datasets permit.

Intermodal gains typically lift terminal throughput rather than line-haul capacity. Carload growth, by contrast, can lengthen transit times when locomotive and crew availability lag behind demand.

Why the Week 28 reading matters

Week 28 falls in mid-July, a period that typically captures peak grain shipments and rising consumer-goods flows ahead of late-summer retail. Continued growth at this point in the calendar signals demand strength carrying beyond the second quarter into early Q3.

Freight volumes across U.S. rail have tracked unevenly since the post-pandemic recovery. Coal carloads have slipped on domestic power-generation trends, while intermodal and chemicals have led gains. AAR's year-to-date running totals help planners track whether weekly softness reflects isolated events or broader demand shifts.

Carriers also benchmark their own weekly disclosures against AAR's aggregate to identify share gains or losses within specific lanes and commodity groups.

What's outside AAR's weekly report

Short-line and regional railroads do not file weekly volumes to AAR; the data covers only the Class I network. Passenger rail movements, operated mainly by Amtrak and various state agencies, fall outside the traffic counts as well.

How Railway Age presents the data

Railway Age, the trade publication that carried AAR's Week 28 release, has covered U.S. rail traffic summaries since the 19th century. Its reporting translates AAR's raw numbers into context: weekly and year-to-date totals against the prior year, commodity-level shifts, and any carrier-level anomalies.

Analysts typically pair AAR's headline totals with network-level data from individual operators. The combination reveals whether volume gains translate into service improvements or surface as congestion, dwell-time increases, or storage charges at interchange points.

What to watch next

AAR publishes the next weekly summary in mid-July. Continued growth at the same pace would extend the year-to-date trend through midsummer; a slowdown would test whether the run reflects underlying demand or one-off shipment timing.