That's why I think it's an infrastructure problem, assuming economic viability. If the current routes date back to the Interwar period (at best) or the Gilded Age (at worst), that will require a lot of route-straightening. There's probably a point at which a passenger-only HSR route starts looking palatable in place of all those upgrades (just run the night train on those tracks) - I just don't know what that point is.
My back-of-the-napkin assumptions were as follows:
- Business travelers generally have to make 9am meetings on time. Sometimes they can make 8am meetings if it's a reliable train and their meeting is close to the train station, or they can get a cab.
- Assume 60-90 minutes from the train station to the 9am meeting location.
- Assume also that 90 minutes is sufficient to make it from your previous location to the departure train station.
- For Chicago-NYC, you "lose" an hour to the time zone change.
- Add in some fudge-factors for platform scheduling, padding, and dwell time as needed.
- You don't want to have a departure time that is too early. Our intrepid businessperson may still be working on a deal at 5pm, and leaving the office at 6pm isn't all that unheard of. A departure time right at peak PM rush may also be a problem with platform and track capacity.
The last point is why a 25% time improvement isn't helpful here. If NYC-CHI takes 14.5 hours instead of 19, a 7am arrival means you're leaving at 5:30pm from NYP, or perhaps a little earlier. (It's 3:30pm from CHI to NYP.) That's starting to crimp what can get done during the day. Anything much earlier than that starts making same-day flights to a hotel a more reasonable possibility - which defeats the purpose of an overnight train from a business proposition. My assumption thus is that overnight trains should generally run 8-ish pm to 7am (local times) or thereabouts.
So for our intrepid traveler from NYP to CHI can leave work at 6-7pm, head downtown, maybe get a decent meal, arrive at NYP at 9:30pm to board the train. Obviously you'd have to leave the Chicago office around 5pm to make it work similarly.