Domestic intermodal container volumes have climbed to all-time highs, posting 8% year-over-year growth on top of multi-year gains, even as truckload tender rejection rates remain stubbornly near 14% going into the historically soft first two weeks of October.

The combination is forcing carriers, brokers and shippers to rethink their Q4 planning. Much of the freight that disappeared from the truckload tender index at the end of September has shifted to rail rather than evaporated, FreightWaves' Zach Strickland argued in a market update this week.

"I know a lot of this freight is going intermodal at this point too," Strickland said. "So not gonna take it as a pure economic signal, but truckload operators and brokers should be monitoring this to see if there is a little bit of easing going on in the market due to this demand side easing that we're starting to see."

Can the rail network absorb 8% more volume?

Intermodal's growth trajectory is the standout data point of the fall. Year-over-year container volume gains of this magnitude are unusual in any cycle, and Strickland is blunt about whether they can continue.

"It does not look sustainable to me at this point," he said, warning that the rail network's fixed infrastructure makes it difficult to manage volume surges of this scale. Any service disruption on Class I rails could create a significant choke point for domestic freight flows that have come to depend on the mode.

For shippers, the practical question is reliability: how long can an 8% growth rate continue on a network that cannot easily be expanded, and what happens to lanes if that capacity ceiling gets tested by weather, crew shortages or equipment constraints?

Why are rejection rates stuck at 14%?

Truckload tender rejections have hovered around 14% — above August levels — and have not retreated despite the calendar flipping to Q4, which historically represents one of the softest freight periods of the entire year. Flatbed and refrigerated rejection rates are both edging higher, while dry van has shown only a modest seasonal dip.

Reefer is being supported by active harvest season demand that Strickland said typically persists through January during winter weather events. That gives produce and protein shippers a more stable backdrop than dry van operators are seeing.

Is it tight capacity or just expensive diesel?

Spot rates tell a different story than rejection rates, and Strickland cautioned against conflating the two signals. Rejection rates are fuel-agnostic. Spot rates are not.

Rising diesel costs are pushing dry van, flatbed and refrigerated spot rates higher. Smaller fleets with heavy spot-market exposure are absorbing those costs where the market does not allow for full fuel pass-through, compressing margins even as headline rates climb. Operators running contract freight with fuel surcharges are in a structurally better position.

What should brokers and shippers watch next?

Three indicators will determine whether the Q4 market softens or stays propped up:

• Whether intermodal volume growth holds near 8% or decelerates as rail infrastructure strains
• Whether the 14% tender rejection rate breaks lower in mid-October or holds into November
• Whether diesel continues to climb and force another leg of spot rate increases independent of capacity

Strickland said it is too early to declare that rates have peaked, given continued supply-demand imbalances and persistent diesel cost pressure. The forward read for shippers and carriers hinges on whether the intermodal surge stabilizes the network or overwhelms it, and whether diesel-fueled spot gains can hold once refiners and retailers reset fuel expectations into year-end.