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.
Special note: This graph seems to be behind. The line for 2009 extends only half way across the 4th quarter. By week 48 it should be 70% of the way across the 4th quarter. I have no information on this apparent discrepency. For an explanation, please contact the Railfax people.
Note: This web site has new tables and graphs every Thursday, late afternoon. So, if I am late or miss a week with this blog posting, you can check for new data on Thursdays.