Why does it take so long to get from Chicago to Kansas City? Well the answer is no. How about a high speed rail operated by Amtrak that goes from Chicago to Kansas City via St. Louis gets implemented. This rail would have a max operating speed of 150 MPH. Stations are Chicago, Joliet, Bloomington-Normal, Springfield (Illinois), St. Louis, Jefferson City, Independence, then Kansas City. It would be the old American Flyers that ran on the NEC that were replaced by Acela Express. It would need crossings eliminated so vehicles nor pedestrians are hit by high speed trains. It will also run on electricity reducing pollution. Bet you can make a lot of money on this. Plus put freight trains on separate tracks so there are no collisions with the American Flyers.
That's in the works as Ozark stated. 110 mph is currently under construction between Chicago and St. Louis. It would be cool to see 150 mph plus, you gotta start with small upgrades. Going that fast will indeed require totally new right of way, and that requires lots of money. In this age of budget cuts, that extra money is hard to come by right now. You are probably familiar with California's HSR project that is estimated to cost almost $100 billion for 220 mph service. Although it's expected to make a profit, thats a huge down payment to come up with. Hopefully it'll happen one day, in our lifetime.
1) In your first sentences, your answer is not related to your question (A "why" question does not indicate a yes/no answer).
2) Part of the problem right now is a long STL layover (3 hours, 40 minutes).
3) Another part is the indirect route. If you want a faster CHI-KCY trip, the Southwest Chief leaves Chicago every afternoon at 3 PM and arrives in Kansas City at 10:11 PM, a trip time of 7:11 (versus CHI-STL-KCY's on-board time of 11:00). Coming back, it leaves KCY at 7:43 AM and arrives in CHI at 3:15 PM, a trip time of 7:32 (and some of this is end-of-trip padding). Compare to CH-STL-KCY's on-board time of 11:20.
4) Let's assume that your proposal were to be implemented, expensive though it would be. If you could "timetable" a train at 100 MPH (remember, 150 MPH would be your top speed, which you'd have to slow down from for any tight turns as well as for bridges you can't get around, not to mention intermediate stops), assuming a 15-minute layover in STL you're basically looking at a six-hour trip. This would give you two sub-markets (CHI-STL and STL-KCY) with three hour trips...sellable, yes, but with one big glitch in that Kansas City and St. Louis are
no Washington and Boston, and there is an almost complete lack of major intermediate markets like the Acela serves. The two metro areas have a combined population of around 4.9 million, while Boston
alone has 4.5 million people, Philadelphia has 5.9 million, Washington has 5.5 million, Baltimore has 2.7 million (on par with St. Louis), Providence has 1.6 million, and Bridgeport-Stamford has 900k, and New Haven has 860k. In essence, you have to gamble that Chicago, half the size of New York, will "carry the water" for the route. The only thing Chicago
might have going for it is a better connection "net" in the region (something which is probably a dubious claim, IMHO, given both the far lower frequencies and messier times involved at the moment)
5) And the problem with #4 is the expense involved for a new, more or less dedicated alignment. I just don't see it happening, given the low populations involved...at least, not before you get a major beef-up of the more conventional lines in the region.