Prech wasn't suggesting any run-throughs through Chicago, but an extension from the Milwaukee end westward.Prech: At one point early on in the Amtrak era, there were a few run-through trains. Chicago Union Station has only two run-through tracks, so that would limit the number of trains able to run through the station and keep going somewhere. Some options would be:
Milwaukee - Detroit
Milwaukee - St. Louis
Milwaukee - Galesburg / Quincy
Other route extensions would require a back-up move, I believe.
For some reason, though, Amtrak feels that Chicago has to be the end of the line.
As for the "some reason" that Amtrak terminates everything in Chicago:
1) Chicago is the maintenance base for a lot of equipment. It's far simpler/easier/cheaper to rotate equipment through Chicago than to set up facilities all over the Midwest.
2) Reliability is much better by breaking things in Chicago rather than running through, which would have delays propagate even more than they do now. This is especially so on the Hiawatha route, which has the tightest schedule in the system.
3) Routes can have different capacity/equipment requirements (particularly the Hiawatha vs. other trains, with no food-service car/business class), so having run-throughs requires equipment (both types and quantities) to match.
4) Since most of the short-distance routes were (and now, all are) state-supported, trying to get a bunch of states together to agree on how to schedule and share costs with a run-through route becomes very difficult.
5) Most folks are either ending in Chicago or connecting to a large number of different trains anyway, so running through would really only benefit a small number of people, which isn't enough to offset the challenges associated with 1, 2, 3 and 4 above.