Not quite my point.
My point was that speeding up the Hiawatha line, whatever the top speed, may be more impactful than doing so to the line between Chicago and Detroit. If you're traveling between those two cities, you're likely going to fly; 3.75 hours from 5.5 won't really make a material difference to that decision. Whereas a 33% reduction between Milwaukee and Chicago makes a daily commute within reach for more people, though the price may very well ruin that advantage.
In other words, context matters.
Still, we're only talking about passenger rail here. Freight may benefit all the same.