I was navigating around Amtrak's web site today and found a new little feature in relation to on time performance.  A roll up report based on the host networks on-time performance and interruptions.  Here's a quick screen shot, to find out more go check out Amtrak's site.

The little icon and "On-time performance..."  is what will get you info on the various routes historical on time performance.  The way you get here from the main page is by selecting the train number and destination or origination of the train you want information on.  When the screen to choose which train comes up the historical tool will show to the right.