It is a myth that there are no proper regular train services in America. Not many by European standards, but there are some. Here, the 13.45 from Santa Barbara to San Diego calls at Fullerton, California. This push-pull double-deck diesel train, the Pacific Surfliner, is hourly between Los Angeles and San Diego, and rather less frequent north of LA. A few per day go as far north as San Luis. Here is the timetable.