Amtrak has cancelled nearly everything that might run anywhere near Chicago, and a lot of other trains as well. Some have apparently been significantly delayed even if they're running. "Server Issues" are the reason - apparently there's some kind of nationwide outage of back-office services required for PTC or at least Amtrak's ability to originate trains. I'm thinking something like Southwest Airlines' issues a few months ago? Was there a server farm in the vicinity of the big tornado where a lot of railroads (including Amtrak, which is officially a railroad) that was the single site providing all or most railroads with back-office services?

I don't see anything on the news channels about it, but it's apparently been going on since early today (3/25).