Quite a few of the CN lines radiating from Chicago, and a pair of lines from other railroads too.
But no restrictions on the FEC where Brightline runs, nor on the West Coast where Amtrak California has been rolling out their own Venture trainsets. And no restrictions on most of the other railway's lines out of Chicago that the Ventures and Chargers run.
They are most certainly involved in the conversations regarding fixes, but considering that the problem isn't specifically of their doing I'm not sure why you think that they should be put out on this.
Dan