There is more documented at this website, most are long ago absorbed by Greyhound or Trailways or out of business by now:
https://www.chicagorailfan.com/greyrail.html
Burlington Trailways buses turn up in Chicago on a regular basis.
Wow, who knew, and the busses even look like they are painted in Chinese Red Paint.............
https://burlingtontrailways.com/history/
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