Intermodal volumes closed out the second quarter with a 17.2 percent year-over-year boost
, according to a report by the Intermodal Association of North America.

Dometic containers set a new record high, rising 16.4 percent during the quarter. International container volume was up 20.9 percent. This was the first time in nearly four years that domestic container growth was surpassed by an increase in international container volume, the Intermodal Market Trends & Statistics Report said.

Despite the higher growth in international containers, domestic container volume saw its 20th straight quarterly increase.

Trailers posted a 5 percent gain during the quarter, but are expected to continue their long-term downward trend later this year. Overall domestic intermodal volume rose 13.2 percent, a gain strong enough to offset the losses in volume in 2008 and 2009 and set a new record for the highest domestic intermodal loadings in a quarter.

Inventory restocking likely played a major role in driving the large increase in intermodal volume recorded this quarter, IANA said. During last year's downturn, retailers aggressively cut inventories to the point where they were so low at the beginning of 2010 that they could not support even a modest rise in consumer spending. As a result, inventory replenishment has resumed and has become a key driver of intermodal growth. Although total intermodal shipments are still below pre-recession levels, they have significantly recovered.