At first, I questioned why you would think they would be limited to SLO-LA, but you might have a point. I depends on how many seats the set provides - if it is substantially less than a Surfliner set, then I could see them restricting them to Santa Barbara-Los Angeles because these trains generally used to run lighter passenger loads, but this would require a cross platform transfer in Los Angeles. The San Luis Obispo train used to have more cars than the five common on most of the other trains. That train was hell to work, lots of passengers south of Los Angeles, lots of cash fares to the north. Crews may have it easier these days with the hand-held ticket machines, but when I worked it we had a wad of cash in our pocket and had to rub credit cards with our ticket punches on the old carbon slips.

Years ago, Amtrak managers had a pretty efficient equipment/crew rotation, made easier because except for holidays and the SLO set all were pretty much five car sets. I don't know about the Los Angeles based crews/sets, but San Diego rotated the trains that laid over there. One set that only went to Los Angeles in the morning would go to the yard after arrival, and would come back out that night to go back to San Diego. One set went to Los Angeles, then would come back after 2-3 hours. The sets were on a rotation, so each train set worked each run in turn and went back to the yard every few days. If there was a problem engine or car, it was switched by San Diego into the next day's set to the yard. Remember that the inventory on the cafe cars is signed out to the LSA, so they stay with their car which is unloaded/inventoried when the set goes to the yard. So they stayed with their car, laying over in San Diego each night, and getting days off when their car got back to the yard. All the San Diego based train crews and Los Angeles-San Diego train crews got home each night, and as I recall each had one split shift that went real high in seniority because crews got full pay after the first two hours off mid trip.

The SLO set had its own rotation, being cleaned each night in SLO. I think it was on Wednesdays it would operate Los-San Diego and return with two sets coupled (with one of the two engines in the middle of the train) At San Diego, the opposite set would be used for the trip back and the other set being left in Los Angeles.

Assuming that Amtrak doesn't want a cross-platform transfer, the Talgo set(s) would have to be in some kind of crew/equipment rotation. Maybe they would be restricted to Los Angeles to San Diego and return?

It got real entertaining when something bad happened and someone had to figure out how to keep trains in rotation and try to get back on time. I was on trains several times that were turned back north at Oceanside with bustitution to/from Solana Beach and San Diego. The craziest day was when SP derailed somewhere between Los Angeles and Santa Barbara (which gives you an idea how long ago I worked for Amtrak). The morning trains our of Santa Barbara and San Luis Obispo got stuck behind the derailment. I was called off the extra board to work a train that left San Diego mid morning, and after laying over in Los Angeles brought the same set back that afternoon. Both the north trains were still stuck behind the derailment, so the yard threw together a Superliner set to replace the first train, and stole our train for the next one. For our train, the two delayed trains arrived coupled together and they took one set to the yard. We had our normal passengers, the ones from both the Santa Barbara and SLO trains, and then the Bakersfield buses arrived, plus we were supposed to now work baggage at most stops. And they didn't call us any more help, so the train had like 500 pissed off passengers with only an engineer, conductor, AC (me), LSA and Custom Class attendant. Conductor told me to put my ticket punch away, so neither of us pulled a ticket the trip back. We had Custom Class passengers (the only reserved seats) stuck in the cafe car, and had passengers standing in the aisles half way to San Diego to San Juan Capistrano. I ended up being pretty rude to the seat hogs. The station agents had to work the baggage car. The conductor called San Diego and warned them that we had overflowing toilets and trash cans. San Diego must have called in extra help. Before we were done unloading, they were fueling the engine, pumping the toilets, pulling trash off and restocking the cafe car. They had to turn that train set back to SLO, and it left 20 minutes after we had arrived.

You had to feel sorry for the LSA's. When the equipment sets got mixed up they had to stay with their car. I don't know what they did to get them back into rotation and days off. I hope their union contract paid them for it.