> What about a train between Chicago and Detroit?

I've ridden the Wolverine, it isn't half bad.

I 100% agree trains might be underfunded in the US. The LA to NY flight will stay preferred to a hypothetical high speed train due to time. It is unlikely ever to be less than 10 hours.

For train rides under 4 hours, and if you can get trains running smoothly (less stops), the time spent on the train and the overall integration of trains is a lot better as a mode of transportation.

NY to Philadelphia is relatively fast. There was a faster train on that route even before Acela (Metroliner). Boston to DC is a fairly long day by train and, while I've done it, no business person who is really on a schedule is going to vs. taking a pretty short flight. (And, if you're really going city to city, both cities have close-in airport options.)