To me, a ‘reasonable case’ would include:
- profitability
- little potential for economic distortions and dislocations
- affordability
- demonstrated need
Ultimately, by big objection is that governments are simply lousy at figuring this stuff out. Look at all the airline failures there have been. But that’s in a free market, where failure means you go out of business, people learn new things about the market, and then business tries again. It’s very much a bottom-up, iterative approach to infrastructure. But if government had chosen the routes (as it used to), you’d find them inefficient, costs would be much higher, and subsidies would keep the whole rickety structure alive. That’s a good description of the air travel network back when government ‘planned’ it.
Let me give you a simple analogy from path-planning on campuses, which I learned in a usability text a few years ago:
The top down approach to designing the walking paths on a campus is that the architect lays out the buildings, then decides how people want to move between the buildings, then designs the pathways and landscaping to match his vision of how foot traffic will travel.
This approach is almost always wrong, and if you walk onto most campuses you’ll find that either the students are forced to walk on the paths provided through the use of fences or natural barriers like hedges, or there will be paths cut into the lawn all over the place as students choose their own way to get to class. But an order definitely emerges. By looking at the wear patterns in the grass you can see a sort of ad-hoc ‘infrastructure’ of packed-down paths created by the students.
So the alternative approach is to build the campus buildings, sod the landscape without any barriers or walkways, and just let students free to walk however they want. Then next year, you find the most heavily traversed paths and pave them. The order emerges from the student’s needs, and not from the vision of the the central authority. This is bound to be far more efficient. But it still suffers from the flaw that over time, as the nature of the student body changes, new classes are added, and new buildings are constructed, the optimal paths will change. Your perfectly efficient walkway system is only efficient for a snapshot in time. So maybe a better approach would be to lay down a material without paths at all - make the whole quad concrete, use astro-turf, or build a series of sidewalks with some large circular ‘interchanges’ so that the are enough paths to always give someone something close to an optimal path.
High speed rail is like the first approach. Smart guys in government analyze traffic patterns, then decide what the best way is for everyone to travel. They build very expensive, very inflexible links to match their vision.
The road system is more like the second approach. Roads can be cheaper to build, and we’re constantly mutating the road network to meet current demonstrated needs. And like the campus that has many pathways with interchanges, the road system is more like a network than a fixed corridor - as needs change, there are enough different paths from one place to another that there is still room to find an optimal path.
Now let’s go back to the campus analogy and see where an equivalent of HSR might fit in. Let’s say there are two very large buildings, and there’s heavy student flow between them. Maybe one has the cafeteria, and another has 2,000 students in it who need to eat in the cafeteria. Here’s a case where you can say that traffic flows will be heavy, and constant, and utterly predictable. So you build a large connecting courtyard, maybe covered, and you put in more doors and wider hallways to allow for lots of traffic. This makes sense.
So I don’t want to see high speed rail lines criss-crossing the country or connecting up 50 different cities or anything like that. But I could be convinced that a run between two major population centers with stable economies might make sense, if you could demonstrate that there’s currently a major bottleneck and can point to reputable studies estimating costs and benefits - and not one produced by an advocacy group, but by a respected engineering consulting firm.
I did a literature search a couple of years ago for such studies, and found a couple that met my standard for what I’d consider a reasonable positive feasibility report. Most did not. There are so many rent-seekers in large infrastructure plans like this who issue ‘studies’ supporting the proposition from a self-interested standpoint that it’s important to hear the voices of people who do not have vested interests in the outcome. Any high speed rail ‘study’ put out by a chamber of commerce or by a city planning board angling for state funds will be highly suspect, yet many of the most-publicized studies come from just such sources.
Here’s an interesting feasibility study done by the Reason Foundation and others, calling into question the assumptions behind the California HSR plan - one of the ones the Obama administration wants to fund. It’s well worth reading: The California High Speed Rail Proposal: A Due Diligence Report (PDF). It’s certainly a critical report, but I think it’s important to hear all sides on such an important issue.