Intermodal volumes surge 6.1% in September, driven by capacity shifts

The Intermodal Association of North America reported a strong 6.1% year-over-year increase in total intermodal volumes during September 2026, marking an acceleration from August's 4.1% growth. This momentum reflects a structural shift in freight transportation dynamics, with domestic containers rising 8.1% and trailers climbing 11.1% annually, while international ISO containers posted more modest 3.8% gains. Year-to-date through nine months, total intermodal volume reached 14.4 million units, up 3.4% compared to the prior year, though international container volumes declined 0.9%, suggesting divergent trade patterns. The sustained growth is underpinned by two reinforcing supply chain factors: elevated diesel prices stemming from geopolitical tensions in Iran and Ukraine, which improve intermodal's competitive economics on shorter lanes, and a critical reduction in trucking capacity driven by regulatory enforcement of driver CDL requirements.

Andrew Sibold, IANA's Director of Economics and Freight Policy, identified April-May 2026 as an inflection point when these capacity constraints began materially shifting freight to intermodal services. This combination of capacity scarcity and cost advantage has proven durable rather than cyclical, suggesting structural modal conversion rather than temporary demand fluctuation. Looking ahead, industry fundamentals appear poised to support continued intermodal expansion. The AI capex buildout, which is consuming significant logistics capacity and driving infrastructure investment in data centers, is expected to sustain freight demand for multiple years.

Sibold indicated that October could replicate September's performance, with a potential December surge driven by restocking, yet he anticipates the absence of typical seasonal troughs. This outlook carries strategic implications for supply chain professionals planning capacity, rate negotiations, and modal allocation for 2027.