Steve Chapman makes a pretty reasonable case as to why Amtrak should be defunded, but the reality of single member districts with Amtrak stations is that isn’t going to happen. The larger problems with Amtrak primarily have to do with the long range routes that are enjoyable from what I hear, but economically disastrous to the agency. Shorter runs such as the Chicago-St. Louis run aren’t profitable, but the subsidy is of the type that the states and federal government aren’t put too far out to continue the service. Where the economic problem comes in is on long run routes such as routes that cross the country.
Amtrak isn’t going away because Members of Congress have lots of constituents who like it, so instead of getting rid of its funding, forcing the agency to restructure into shorter routes and perhaps providing infrastructure money to make it faster and more attractive is far more likely to produce an agency that isn’t going to be self-sufficient, but will provide regional transportation.