Yes they do. California Rail PAss (21 days in CA), Florida Rail Pass (365 days Florida Resident in FL)), NA Rail Pass (All of US and Canada 30 days). Explore America (45 days), USA Rail Pass (Foriegn visitors only).
You can find more information on the various passes mentioned above, by clicking here. That link will take you to Amtrak's webpage concerning rail passes. From there you can link to a page that describes each type of pass.