I guess there are portions of track capable of 110 MPH speeds. This MLive story from about a year ago says track improvements have been made between Porter, IN and Albion, MI. There is funding available for improvements into Dearborn.
https://www.mlive.com/public-interest/2021/05/amtrak-will-speed-up-trains-on-trips-between-detroit-chicago.html
I think I also remember discussions about a station near Romulus, probably Wayne or wherever those tracks are south of Michigan Ave. There is a Smart Bus terminal near Middlebelt and Google Maps shows vacant land. The thinking at the time was to run a shuttle bus between DTW and the terminal for passengers heading to Ann Arbor and points west. There is already a bus running from DTW to Ann Arbor on a regular basis.