Thing is, the task of combining and separating trains is done all the time at Albany, San Antonio, and Spokane all the time and was routine at Salt Lake City with the Desert Wind, California Zephyr, and Pioneer being separated or joined together. And multiple locomotive changes are made routinely at Washington DC (and New Haven before that.) It's not like this is a new concept.
Let's look at the options.....
1. Combining/Separating the Southwest Chief with/from a "Texas Chief" at somewhere like Wichita, Newton, or even Kansas City. (Wellington Kansas is the actual point where the routes diverge and the town is large enough to warrant a stop, but I don't know if there is the track space or facilities to combine and separate trains there. It makes the most sense logistically to do it in Kansas City.)
Pros: Convenience that through passengers do not need to change trains or even change cars and can ride on one ticket to Kansas City, Chicago and points between.
Cons: Temporary loss of some electrical power with exception of emergency lighting.
2. Passengers change trains at Newton, Wichita, or Kansas City in the middle of the night.
Pros: A.No Loss of power to either train. B. Better than no train service at all. C. Less expense and fewer logistical issues than combining and separating trains.
Cons: A. Tough sell to potential paying through passengers who would look at the middle-of-the-night connection in the middle of nowhere and decide to check out
www.southwest.com. B. Tough sell to advocacy groups who would be working hard to get the service reinstated.
3. Through "Texas Chief" all the way from Chicago to Fort Worth.
Pros: Convenience of one train all the way without the hassle of connections and no logistical issues of combining or separating trains.
Cons: A. Most expensive option for multiple reasons and longest to actually bring to fruition. B. Long laborious negotiations with BNSF to allow a second passenger train between Chicago and Wellington, if they ever agree to it at all.
4. Motor Coach Service between Oklahoma City and Wellington/Wichita/Newton/Kansas City to connect SWC with Heartland Flyer.
Pros: A. Least expensive option that connects the services. B. Good incremental measure while logistics of getting a train between Oklahoma City and Wellington are worked out.
Cons: A. Even tougher sell to potential through passengers connecting from a bus to a train in the middle of the night in the middle of nowhere. B. Tough sell to advocacy groups.
5. Status Quo with no service at all between Oklahoma City and points North and East.
Pros: A. Least expensive option. B. Requires the least effort and advocacy.
Cons: A. Most restrictive on travel options. Back behind the wheel or going to Oklahoma City to fly Southwest. B. Region foregoes the potential economic benefits of having a passenger train service that region.