U.S. intermodal volume climbed 10.4% year over year in the week ending Oct. 10, to 302,252 containers and trailers — the strongest signal yet that freight is shifting from road to rail.

Total weekly traffic across U.S. railroads hit 534,256 carloads and intermodal units, up 7.2% from the same week last year, according to Association of American Railroads data. Carload traffic contributed 232,004 units, a more modest 3.4% gain. Intermodal is doing the heavy lifting, and then some.

The context matters. High diesel prices and tightened regulatory enforcement have squeezed trucking capacity, and shippers are voting with their containers. Intermodal's weekly growth is running at roughly three times the carload pace — the same pattern FreightWaves flagged earlier this month.

What's moving on the carload side?

Eight of ten carload commodity groups posted gains versus the same week in 2025. The leaders were a steelmaking story:

• Metallic ores and metals: up 19.7%
• Forest products: up 9.6%
• Motor vehicles and parts: up 9.4%

Two groups declined. Coal slipped 2%, and farm products excluding grain and food fell 5.6%. The metals surge fits a steelmaking chain that keeps humming; the coal slide fits, well, coal.

What does this change for shippers and forwarders?

The year-to-date numbers frame the trend. Over the first 40 weeks of the year, U.S. railroads carried 11,379,949 intermodal units, up 4.4%, alongside 9,142,597 carloads, up 2.7%. Combined traffic reached 20,522,546 units — a 3.6% increase. That's more than 70 million units on an annualized basis, and the growth curve is steepening, not flattening.

For shippers, the practical question is whether rail can keep absorbing demand if truck capacity stays tight. Intermodal's 10% weekly jump suggests boxes are already finding their way to ramps. For forwarders, it means intermodal quotes deserve a fresh look on lanes where diesel surcharges have eroded the trucking discount. For carriers, it's volume without the chassis of a rate war — demand arriving on its own.

North America follows the U.S. lead

The pattern holds across the continent. Nine reporting U.S., Canadian and Mexican railroads moved 386,946 intermodal units for the week, up 9.1% year over year, and 338,457 carloads, up 2.6%. Combined North American traffic totaled 725,403 units, a 5.9% gain. Year-to-date volume across the three countries stands at 28,096,978 carloads and intermodal units, up 3.1% from 2025.

Intermodal outgrowing carloads by three to one, in both the U.S. and North American counts, is not a one-week anomaly anymore. It's a queue forming at the ramp.

If diesel stays expensive and enforcement stays strict, the modal shift has room to run. The next few weekly counts will show whether railroads can hold service levels while they carry it.