http://railfax.transmatch.com/
Here is an example of the information available on this web site. This graph shows Total Traffic for 2008-2009 vs. 2007-2008. There are more graphs and tables on the web site showing data by railroad and by commodity.
From the graph, it looks like rail traffic is picking up. But is this just a seasonal effect, or is this a sign of economic recovery. Keep watching this blog for weekly updates.
Note: This web site has new tables and graphs every Thursday. So, if I am late or miss a week with this blog posting, you can check for new data on Thursdays.