However traffic declined 1.6% from July on a Seasonally Adjusted (SA) basis.
This graph shows U.S. average weekly rail carloads (NSA). Traffic increased in 16 of 19 major commodity categories year-over-year.
From AAR:
• U.S. freight railroads originated 1,179,447 carloads in August 2010, an average of 294,862 carloads per week. That’s up 5.7% from August 2009 though down 11.6% from August 2008 on a non-seasonally adjusted basis. It’s also the highest weekly average for any month since November 2008 and reverses a string of three straight months in which average unadjusted carloads fell in absolute terms.As the graph above shows, rail traffic collapsed in November 2008, and now, a year into the recovery, traffic has only recovered part way.
• However, on a seasonally adjusted basis, U.S. rail carloads fell 1.6% in August 2010 from July 2010. As the chart below ... shows, on an unadjusted basis rail traffic almost always increases from July to August. In that chart, note the upward slope of the line segment from July 2010 to August 2010. That slope is not as steep as the line segments for the same period in most other years on the graph, or for most prior years not shown on the chart. In a nutshell, that explains why seasonally adjusted rail traffic in August 2010 is down a bit when unadjusted traffic is up.
excerpts with permission