Yes, there would be ridership for perhaps an additional SF-LA train a day in addition to the Coast Starlight, mostly tourists and not business people. The schedule will simply be too slow.
But if Caltrans uses coaches similar to the Surfliner/San Joaquin/Capitol Corrdior with only a snack car/lounge on an 11 hour-plus journey, it won't be THAT popular even with tourists. Riders would likely demand a full diner and a little more comfort. UP might allow the train to meet the printed schedule, but I doubt that printed schedule is going to be any faster than the present meandering journey of the CS each morning up from Los Angeles to Oakland, even when it makes it on time by 9:30 p.m. or so.
As for the Central Valley, are we to take from your posting that you don't believe the Hi-Speed Rail project has a ghost of a chance of succeeding??
It is not Amtrak, nor CalTran's, place to really care who rides the train in terms of demographics. Businessman, tourist, college student, military; they are all exactly the same when it comes to being a passenger. If they can (and will) sell seats, who are they to care? And have you had experience with the California cafe cars? The food selections provided are actually quite good. The San Joaquin route is already nearly 7 hours, btw. With the track improvements that are coming along the coast route in the next few years, that current 11 hours will drop considerably.
As for High Speed? It has no chance at all of succeeding in the next 10 years; it will take that long before the first train up the Central Valley from Modesto to Bakersfield to be built and running. Will a bullet train be built? I had high hopes, and still do have hope, but I'll be in my 50's before I can step foot into a trainset and ride from San Francisco to LA with the rate things are going. In the meantime? All Aboard the Coast Daylight!
It's only an educated guess, but I imagine that planners look very, very carefully at the demographics of any route that they work on. Do you really want to argue that the addition of the Parlour Car on the CS had no relationship to the type of passenger that Amtrak saw riding, or wanted to encourage to ride, on the particular train? An enhanced snack car, which is what the snack/car lounges are on the San Joaqins/Cap Corridors, works well for this route.
Comparing ridership between the coast route and the San Joaquin Valley is apples to oranges, IMHO. The majority of riders on the San Joaquins are traveling from one intermediate stop to another on a corridor with many viable working-class cities and towns, and where air service is either non-existent or very expensive for the median wage earner in the valley. (Conductors on these trains joke about Glad Bags being called "Valley Samsonite.") The type of rider and the average length is taken into consideration by rail planners in determining what kind of amenities should be/need to be offered. Only a small percentage of San Joaquin riders go the 7-hour bus/train jaunt between Bakersfield/LA and Oakland/SF.(I do give credit to Caltrans for reworking over and over the menus for these trains and finally, after many years of testing and surveying, coming up with what appears to be a popular concept.)
In contrast, the coastal route has far fewer residents than the Valley route, except at the endpoints. Between San Luis Obispo and San Jose, I doubt there is a potential for daily ridership anywhere near what the San Joaquins generate, esp. between Bakersfield and Fresno, and Fresno north to Stockton. The evidence for this is in the Caltrans plans for the route itself: a single daily daylight run leaving a little earlier from SF and LA than the present CS, and arriving a little earlier. If a new train is going to complement the CS, it will need to offer amenities comparable to the CS.
I'm curious also where all these track improvements will result in a big drop in the present 11-hour running time along the coast. Double-tracking the tunnels through the Simi Valley? Reworking the scenic but very slow route between Gaviota and San Luis Obispo? Realigning the tortuous routing between Watsonville and Morgan Hill? And with Caltrans having robbed Peter to pay Paul, by moving a huge amount of capital funding from non-Hi-Speed-Rail projects to the Hi-Speed project, where would the money come from to do all of these supposed improvements? Is the UP going to fund them?
BTW, the rumors out of Sacramento are that Gov. Brown will announce a revamp of the Hi-Speed rail project in the next month or two, emphasizing hi-speed trackage outside of the SF and LA areas i.e. The system would feature trains running on regular, or existing tracks in urban areas, and only begin running at fast speeds on tracks that would be built more cheaply in outlying areas. Supposedly that will bring the $98 billion price tag down considerably and mute environmental outcry from those living along the SF Peninsula. Not sure how he handles the concerns of Valley farmers who complain about fields being bisected and Valley towns worried that the route bypasses them and puts their existing Amtrak service in jeopardy.
