I've been working on graphing Amtrak's ridership over time. The Bureau of Transportation Statistics has monthly data going back to 1991, so I simply summed 12-month periods to create moving averages. Older data from 1972 (the first full year of Amtrak operation) to 1990 came from a forum post I found, though I'm not sure how reliable that is.
But the gist is, things are looking up. I hope that Congress will pull back from the idea of cutting Amtrak funding, considering that more and more people are turning to the rails.
I may have to make some companion graphs for highway and airline travel, which are showing different patterns at the moment.