Performance Improvement Plans.PIPs?
A 2008 law required Amtrak to prepare Performance Improvement Plans for each of the long distance routes. You may still be able to find the reports floating around the internet. (Not entirely sure, though, as I haven't searched for them for a number of years.) Essentially, the reports laid out suggestions for improvements to the routes, including schedule changes, new Thruway connections, staffing changes, and more. A few of the suggested improvements were put in place (one that comes to mind is the Newton - Wichita - Oklahoma City Thruway connection to/from the Southwest Chief and Heartland Flyer) but many were never acted on.