I was on the 50/51 on Wednesday down and back to WSS. Apparently signals were down between WSS and STA (due to a lightning strike), which resulted in 51 (which was on time) being delayed in STA for a couple hours, behind a backlog of freights... and things just snowballed. After getting home, I wondered why the train had lost more time. I called Amtrak and they said that as it approached CHI it got into heavy freight traffic. Obviously Wednesday's 50 also ran into the same signal problems (6 hours and 56 minutes late into NYP).
I know that there's been a number of external things that Amtrak has not had power over. A warehouse fire near IND, a freight derailment near CHI, CSX working on the tracks at CLF, signal outages... all these things are unusual, but can and do happen, as is evidenced by the Cardinals performances. I don't know why, perhaps track work is generally completed? But I've heard that the Cardinal has better on time performance in the fall. I'd take the chance with her between CIN and WAS, but then I enjoy just being on the train, and if she's late well... that's all part of the experience.