The Association of American Railroads recorded a continuing year-over-year uptick in U.S. rail traffic for Week 38, according to Railway Age.

The headline "AAR: U.S. Rail Traffic Uptick Continues in Week 38", carried by Railway Age, extends a string of positive weekly comparisons into the late-September measurement period. AAR compiles originating carload and intermodal data from the U.S. Class I freight railroads each week and benchmarks it against the equivalent week of the previous calendar year.

What does the AAR weekly release cover?

The association's weekly summary aggregates originating carloads across roughly 20 commodity groupings. Major categories include:

• Coal
• Grain and grain mill products
• Chemicals
• Petroleum and petroleum products
• Metallic ores and metals
• Forest products
• Motor vehicles and equipment

Detailed weekly carload counts by commodity appear alongside intermodal container and trailer lifts, with both streams reported against the equivalent week of the prior year.

Week 38 in the AAR calendar covers the seven days ending in mid-to-late September. That window sits ahead of the autumn agricultural and consumer-goods peak and falls inside the Class Is' third-quarter reporting period.

The trade group's data aggregates weekly submissions from BNSF Railway, Union Pacific, CSX Transportation, Norfolk Southern, and the U.S. operations of Canadian National and Canadian Pacific Kansas City.

What does an "uptick" mean in AAR's framing?

An uptick, in the AAR's standard usage, signals that the week's combined carload and intermodal volume ran above the comparable week of the prior year. AAR reports the two streams separately, and a positive change in either can drive the headline characterisation.

Sustained upticks across multiple consecutive weeks typically reflect firm bulk commodity demand, containerised consumer-goods volume, or a combination of the two. The same drivers tend to underpin the Class Is' car-mile and revenue performance over a multi-week window.

Why does the Week 38 print matter?

The Class I freight network entered the year with operators projecting volume growth against the prior-year baseline. A continued run of positive weekly comparisons through the year's 38th measurement week indicates that the cumulative year-to-date figure remains in growth territory heading into the close of Q3.

The pattern matters for shippers evaluating rail service reliability and for analysts modelling the Class Is' revenue per carload and operating ratio ahead of third-quarter earnings.

The persistence of an upward volume trajectory into late September also lines up with rising demand from the Midwest grain harvest and intermodal flows tied to early fourth-quarter retail inventory positioning. Higher originating carloads translate directly into car-mile revenue, while stronger intermodal lifts underpin the container segment that has supported much of the Class Is' volume growth in recent reporting periods.

What should shippers and analysts watch next?

The Week 39 release will close out September and provide the final weekly print before the Class Is begin publishing third-quarter operating data.

Volume trends through the autumn peak — grain shipments from the Corn Belt, intermodal demand ahead of the holiday retail season, and coal stockpiling ahead of winter — typically drive the network's utilisation curve into the fourth quarter.

A confirmed continuation of the cumulative gain in subsequent weekly reports would support the Class Is' full-year volume guidance, inform shipper-carrier contract discussions, and reinforce confidence in network capacity through the back half of the year. The first Q3 operating data updates from the Class Is are expected in mid-October.

The full AAR Week 38 release with line-item commodity counts and intermodal totals appears in Railway Age's underlying report.