For one, there's no "talk" of it. Two, the Chief has never been at the top of any list of cuts that people throw around (usually it's the Sunset that is in the crosshairs). Three, the current Amtrak (I say "current" only because I don't know how decisions were made 20-30 years ago) isn't going to randomly discontinue a route just for the heck of it. Four, based on the PRIIA rankings, the Southwest Chief is towards the top of long-distance trains. Five, it serves three states (Illinois, Missouri, and California) that put lots of money into supporting passenger rail (and even if states don't pay for the long-distance trains, they do value their existence as part of the statewide network), on top of lots of local political support that is very valuable to Amtrak.
Again, I am not saying either way, just trying to weigh known facts.
1. I have heard talk of it. Not from Amtrak, but others.
It won't happen. Thankfully, current Amtrak management (unlike some previous iterations) is not entirely stupid. The SW Chief provides the only decent connection between the 2nd largest and 3rd largest metropolitan areas in the US (along with the 12th largest). Rerouted? Yes; the particular intermediate points are relatively unimportant, apart from Albuquerque. It's already been rerouted once (within Illinois) to its benefit. Cut? No.
Worst case scenarios: If there's a real budget crunch, The Cardinal and Sunset Limited would certainly be cut first, so I wouldn't worry about the SW Chief unless that happens. Amtrak management has been quite clear that three-a-week is bad, and the history shows them to be correct; Amtrak will keep trying to make these trains daily, but if there's a crunch they may decide to drop them. If times got tough, they might also consider cutting the Palmetto in favor of the Silver Meteor, given that the Palmetto mainly serves states (South Carolina and Georgia) which provide no money or political support. Other worst case scenario: If there were a crunch due to an equipment shortage of Superliners (perhaps multiple major crashes), then again the Sunset Limited would be terminated first, and if more equipment were needed the California Zephyr would likely be shortened to run from Chicago to Denver (or perhaps Glenwood Springs or Grand Junction). (The Zephyr uses a *lot* of equipment for the 'west of Denver' service and gets relatively poor ridership between Reno and Glenwood Springs.)
Given that BNSF has apparently actually offered to host the SW Chief on the line through Amarillo, I think the Chief is in no danger.
Fred Frailey in _Trains_ is being completely speculative in suggesting that BNSF will demand that Amtrak pay for double-tracking on the Transcon route, and I believe he is simply wrong. He's made false, pessimistic claims before. BNSF has in fact already stated its intentions to double-track the entire Transcon for freight purposes, so such a demand would be obviously bogus, and would probably inspire a successful Amtrak lawsuit -- I don't think BNSF would pull bogus nonsense like that. As one commenter to his article wrote (sic):
In past article published in "Trains" it was quoted by BNSF that there would be no addition cost to Amtrak if they were to change to the trascon route .
(Note, however, that this may explain why Amtrak is putting off rerouting as long as possible. The longer Amtrak waits, the more of BNSF's double-tracking program will be *finished* by the time Amtrak moves, which would allow better on-time performance.)
Now, there is some potential difficulty in the Wichita area where BNSF runs trains directionally. Thie means they run northbound trains through Wichita, but they run southbounds on a completely different route, so for them it's double-tracked, but following BNSF's route would bypass Wichita and Newton southbound (no good). However, the only "new" part of this for the Southwest Chief would be from Newton to "Mulvane", and of that, the section through downtown Wichita is already double-tracked -- and Wichita has room for station tracks to get the trains off the mainline while stopped. More double-tracking between Newton and Mulvane was already proposed for the proposed Wichita-Oklahoma City service, and Kansas, or even Wichita alone, might be willing to pay for that. It's certainly a lot cheaper than trying to maintain the Raton Pass line; BNSF's desired double-tracking for the *entire* Wichita-OKC Heartland Flyer extension was priced around $108 million, and this would be a small subset of that.
More worrisome is the cost of station construction/rehabilitation. Remember, new stations have to be compliant with the new ADA level-boarding rules. Rebuilding Wichita Union Station with 15" platforms and elevators is an expensive proposition, and building a new Amarillo station could easily require a passenger siding too. Hopefully the cities will realize that this is of value -- particularly Wichita, where the train station could be made ready for the proposed Heartland Flyer extension and proposed future daytime service to Ft. Worth at the same time as it is prepared for the Southwest Chief.