Source: Intermodal Association of North America & American Association of Railroads.
Rail transport trends in the United States underline a significant shift of intermodal traffic to the advantage of containerized freight. While rail intermodal container traffic (container on flat cars; COFC), both ISO and domestic, increased, the number of trailers carried by rail (trailers on flat cars; TOFC) declined. This represents a significant shift in the TOFC/COFC balance; 55%/45% in 1990, 25%/75% in 2000 and 9%/91% container in 2020. TOFC has thus become a marginal segment of intermodal transportation used for niche services, most of them point to point.
58% of the containers handled in 2005 were international (maritime) containers, while domestic containers accounted for 23% and trailers 19%. About 25% of all international cargo moved by rail is transloaded into domestic containers. COFC traffic peaked in 2007 and declined in 2008 and 2009 due to declining import demands. As of 2018, intermodal rail traffic recovered to pre-2006-07 traffic levels. The Covid-19 pandemic saw intermodal rail volumes decline in 2020, However, the demand surge from late 2020 resulted in record intermodal traffic levels in 2021, creating several pressures on system capacity. This raises the question of if intermodal rail has reached its market potential in the United States or if there is additional growth to be expected.
One of the core advantages of COFC versus TOFC concerns double stacking, involving a much higher utilization density of rail assets. Several large American trucking companies are also converting to containerization, thus relying on COFC as opposed to TOFC. For instance, in 2009, citing energy and cost advantages, major LTL shipper Schneider National converted its entire intermodal fleet to containers. JB Hunt, with the largest fleet of domestic 53-foot containers, has also converted to COFC operations.