I'm not sure that makes sense as a single rail route. If Toronto and Detroit are intermediate stops on a line from NY to Chicago, that would mean the train either goes the long way around Lake Ontario (pointlessly adding travel time) or it goes to Toronto via Niagara and then doubles back west (pointlessly adding travel time for NY-Detroit-Chicago passengers).
Really, Lake Ontario makes any NY-Detroit train line much longer than it could be otherwise.
Really, Lake Ontario makes any NY-Detroit train line much longer than it could be otherwise.