In July, monthly average carloadings of oil and petroleum products were near 16,000 carloads per week, according to the Association of American Railroads (AAR). The increase in oil volumes transported by rail reflects rising US crude oil production, which reached an estimated 8.5 million barrels per day in June for the first time since July 1986.

In its latest report, for the week ending 16 August, AAR noted that compared with the same week in 2013, carloads of petroleum and petroleum products were up 19.5% to 15,653 carloads.

AAR estimates that more than half of the nearly 460,000 carloads tracked in its petroleum and petroleum products category from January through July consisted of crude oil, up from around 3% in 2009. With the average rail tank car holding around 700 barrels of crude oil, about 759,000 barrels of crude oil per day were moved by rail during the first seven months of 2014, equal to 8% of US oil production.

Proposed rules published in August by the US Department of Transportation seek to improve the safety of tank cars will affect how crude oil is moved by rail, particularly trains that carry 20 or more carloads of oil. The proposed rules would require new oil tank cars constructed after October 2015 to have thicker steel and require retrofitting of existing tank cars. Voluntary actions by railroads in anticipation of the new rules have resulted in reduced speeds and increased inspections.