[bubuga]

> It seems like you are much smarter than the rest of us.

I'm not smarter than the rest of us. I just happen to be a researcher in the field of railway engineering, specifically in the design of high and very high speed tracks for conventional high-speed rail.

> Would you please tell us plebs what the fatal flaw is?

The main issue with very high speed rail is the cost required to build and maintain infrastructure that must meet such precise tolerances to keep the transportation system safe and reliable and the track usable for human transportation. Technology is still far away from providing a solution for speeds below 400km/h, and the solutions that are currently available are simply cost-prohibitive.

The problems associated with this project are further compounded by the uncertainty of the whole vehicle solution.

Then there are the physics problem. Just for a brief glimpse on the true nature of the problem, in moderately stiff soils a vehicle traveling above 700km/h triggers a response from the soil that is much like the sonic boom triggered by supersonic planes, but with Raileigh waves. This phenomena is already a major problem in some railway lines operating at lower speeds (in Sweden, for example, where a high-speed track crosses an unusually soft soil), and manifests itself in vibrations that are measured in centimeters. Currently, the only available solution to this problem is essentially reducing the traveling speed on regions where the soil stiffness is low. Yet, in hyperloop's case these issues aren't rare: they are the norm.

Adding to the problem, speeds above 700km/h mean that the vehicle clears a span of around 200m in 1 second, which means that even with the vehicle's load the entire section must have an elevation delta in the milimeter range just to limit the vertical acceleration alone. This level of precision is unheard of in civil and railway engineering, and is something that is very expensive to pull off. Now, consider this issue while adding to the mix issues such as natural changes in the region's relief. These levels of precision require a straighter line with lower inclinations, accompanied with larger turn radii. This means bridges and tunnels for hundreds (if not thousands) of kilometers.

Meanwhile, even high-speed railway has serious feasibility problems, to the point where only a hand-full of high-speed railway lines manage to turn a profit ( Paris-Lion for example).

Meanwhile, in the real world the hyperloop hype competes with air travel, which doesn't require trillion-dollar infrastructure construction and maintenance costs, is very flexible, and is far cheaper to operate.

The investment in high-speed railway lines for travel speeds between 300 and 350km/h only rarely makes sense. That's the main reason why today only a few operators have spent money on that sort of infrastructure, and the vast majority of those operators did only so for political and propaganda reasons. Increasing the infrastructure bill a few orders of magnitude to get the exact same thing that are offered today by conventional rail and air travel is simply unheard of.