I am a student at the University of Illinois at Urbana-Champaign. During breaks, I ride the Amtrak Illini and Saluki trains to and from my home in the suburbs of Chicago. On my way back to school in January we were flying through the South Side of Chicago and that got me wondering what is the maximum speed on that line. It felt like we must have been going at least 90 miles per hour but I did some research and I could not find any information about the speed limit on that line. The train consisted of several Superliner cars pulled by a lone Amtrak Midwest Siemens SC-44 Charger. I would appreciate any insights that you can provide.