There are a few areas in the United States where population density and traveler interest have allowed rail transit to be a popular option for intermediate-distance travel. The Northeast Corridor is one of these, as well as the area around Chicago, and perhaps Northern California. And, most relevant to our interests, the area between Vancouver, B.C. and Eugene, Oregon. Within a 450 mile distance, there are three major metropolitan areas with populations over a million people, along with many other smaller towns.
The Amtrak Cascades is suited for this relatively short run: it uses one-story cars (unlike the two story Superliner). It includes a business class car and cafe car, but does not include any sleeper service. The trains run every day, and are frequent enough that someone could (if they chose) travel on them on short notice. Currently, some of the trains are supplemented by bus service on the Eugene-Portland and Seattle-Vancouver, B.C. portions of the route. All of the schedules between Portland and Seattle are actual trains, however.
The Cascades line is an example of how American cities can, indeed, use rail transit as a fast, modern and comfortable form of practical transportation: between Portland and Seattle, for example, it is probably comparably as fast, and much more comfortable, than taking an airplane.