The short answer is, "yes." I've ridden on it. The slightly longer answer (as another commenter has pointed out) is that it depends on the weight of the train versus the weight of the hyperloop. I see no fundamental reason to assume that the hyperloop is lighter than the train. It could be so, but then, we could make smaller and lighter trains, too (light rail).
Plus you don't get the same natural banking off the walls he talks about, which is relevant at these speeds. While rail could bank, you better be going at the right speed when doing so, too slow and you just fall laterally off the tracks.
This is a problem even when you are at grade. The solution is known: tilt-trains. The track is banked such that the train will not fall over if it has to stop on the curve. The passenger cabin then tilts with respect to the wheels so that it always feels like the floor is "down" regardless of the speed that the train goes around the curve. The radius of curve sets the maximum speed the train can travel around it.
A bigger factor is that the efficiency of a train depends on having all the cars connected to each other. With the hyperloop, the pods are spaced out, so there's no need for the structure to bear the load of a bunch of them at once.
Turn down the nastiness. It's totally non-obvious that this isn't overshadowed by the weight of the tube. And it does carry a motor with it, just not one that's responsible for initial acceleration or for large air resistances.
Flippant comments like "Did you actually read the PDF?" are exactly the kind of needless small escalations that destroys the tenor of commentary at HN. Any time you write that, you could be writing "It's discussed on page XX". If the comment doesn't deserve a cordial response, then just downvote and move along.
He responded to your points about the linked article. You went back to discussing why his language was out of line. Now you're destroying the tenor of commentary. Just append the etiquette suggestion to your previous post.
You can't edit a comment that's more than an hour or so old. Reasonable people can have disagreement about the ground rules for online discussions, and it's helpful to get everyone in the same page in a constructive way.
The weight of a 10' diameter steel tube with 1" wall thickness is 125,000 lbf per 100 feet. Note that does not include the reinforcing braces, that is just the plate. The actual weight could be easily 2-4x greater. It also doesn't include the weight of the solar array.
My bet is that it's not significantly different to compare a light rail (subway-like) system to a hyperloop in terms of weight.
The weight of the track ballast alone is more than that. Gravel is about 100 pounds per cubic foot, and you need about 12 cubic feet of ballast per foot of track, or 127,500 pounds.
Then you get to add the rails and ties (or concrete sleepers), plus the vastly more heavy rolling stock.
The reason I said that the weight of the tube doesn't enter into it is because the tube isn't moving. The only thing that matters in terms of energy use is the rolling stock.
You can't just make lighter trains; heavy rail is heavy because it has high capacity. These vehicles can be much lower-capacity per vehicle because the speed is very high, which means you get equivalent throughput even with much smaller per-vehicle capacity. It's just like how you can get the same amount of water through a high-pressure, low-diameter pipe as through a low-pressure, high-diameter pipe.
So yes, you could make the rail lighter, but in order to match the proposed passenger throughput, it would have to go 700mph. Good luck with that.
I would be very surprised if the numbers really work out the way you claim: that the weight for carrying a passanger is similar for trains and a tube, and that the weight advantage of a tube comes essentially from 3x speed allowing for a one third the linear density of passengers. Do you have a cite?
No, this is just back-of-the envelope, admittedly. But the three factors that determine how many people you can move past a given point per unit of time are the frequency of the vehicles, the capacity of the vehicles, and the speed of the vehicles, so if you want to match the throughput of the proposed Hyperloop, but with rail traveling at 164mph, you have to either make the vehicles more frequent or higher-capacity, or both. I would expect rail to be much less frequent, at least if typical rail conventions are followed, meaning you'd need much higher-capacity vehicles, combined with the engines to bring them up to speed (which move along with the train). It doesn't take that much weight to get past what you could reasonably support on a pylon in a median... there's a reason inter-city rail isn't built this way.
> But the three factors that determine how many people you can move past a given point per unit of time are the frequency of the vehicles, the capacity of the vehicles, and the speed of the vehicles
As a matter of fact, only the frequency and the capacity matter. Speed matters to passengers but not to the amount of people you can move.
The hyperloop as proposed actually has fairly low throughput; conventional rail systems, particularly of inter-metro variety where high throughput is most important, best it easily. 28 passengers per capsule at a capsule every 30 seconds makes 3360 pph during rush hours. RER line A averages 30000 passengers per hour over the entire year, with rush hour capacity being much higher.
And if someone would like a long-distance example, at its busiest the line between Tokyo and Osaka sees up to thirteen trains per hour each capable of carrying around 1300 people.
> the three factors that determine how many people you can move past a given point per unit of time are the frequency of the vehicles, the capacity of the vehicles, and the speed of the vehicles
Yes, I guess you're right, but the maximum frequency is bounded by vehicle length and speed (you can't have a vehicle pass every thirty seconds if it takes more than thirty seconds for a single vehicle to pass a given point).
The longest TGV and Shinkansen consists are around 400 m, so they pass a given point in 30 seconds at about 50 km/h (30 mph). Of course there's spacing for safety and so on, but 50 km/h is so low that it's really a factor in practice unless you also have non-HSR traffic on the line.
A bigger factor in practical capacity is loading and offloading people and switching near termini.
The short answer is, "yes." I've ridden on it. The slightly longer answer (as another commenter has pointed out) is that it depends on the weight of the train versus the weight of the hyperloop. I see no fundamental reason to assume that the hyperloop is lighter than the train. It could be so, but then, we could make smaller and lighter trains, too (light rail).
Plus you don't get the same natural banking off the walls he talks about, which is relevant at these speeds. While rail could bank, you better be going at the right speed when doing so, too slow and you just fall laterally off the tracks.
This is a problem even when you are at grade. The solution is known: tilt-trains. The track is banked such that the train will not fall over if it has to stop on the curve. The passenger cabin then tilts with respect to the wheels so that it always feels like the floor is "down" regardless of the speed that the train goes around the curve. The radius of curve sets the maximum speed the train can travel around it.