A colleague at the University of Minnesota whose work on these things passes peer review makes the same case.
Actual [Amtrak] ridership is highest in the Northeast corridor, where the Acela service, along with other conventional passenger rail runs today. The other big Amtrak markets are between San Diego and Los Angeles, between Sacramento and the San Francisco Bay area, between Seattle and Portland, and between Chicago and a variety of midwestern cities, in particular St. Louis.There are two problems, though. First, anybody with a serious case of Potomac Fever thinks almost exclusively in Grand Visions. Second, state governors and passenger rail authorities are quite happy to have Grand Visions paying for projects that ought more properly be financed locally.
Corridors that get traffic now with relatively slow service are more likely to get higher levels of demand when upgraded (made faster and more frequent) than corridors that get almost no ridership now. This argues for (1) incremental upgrades where the benefits outweigh the costs, (2) focusing on specific proven markets rather than trying to connect random large cities.
We should be looking for routes where train is more cost-effective than either driving or taking an airplane. This distance is certainly less than 600 miles for most of the US, under current costs of travel. (Once we have proven we can connect large places closer than 100 miles, we should connect large places less than 200 miles, and then expand outward. We should not start with a grand vision which will simply collapse of its own weight). We should also be looking for routes with large trip generators at either end.
This is not to say there are not segments which could productively be (and are) served by rail. The Northeast corridor is one. Chicago to Milwaukee is one. Los Angeles to San Diego is one. There are a few others. The key point is they are local serving, and should be locally supported. There is no need for US federal involvement. If the projects are worthwhile, the states and cities and private railroads should fund them. Almost all the benefits are local, the costs should be borne by those who benefit.Local governments seem quite willing to appropriate funds for road salt and cold mix, but somehow buying railroad cars or multiple train paths from the local freight carrier is for somebody else to do.