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> which would seem to be more efficient. Why? More cars per passenger would seem to mean a higher operating cost per passenger as each car needs a full drive t

> which would seem to be more efficient. Why? More cars per passenger would seem to mean a higher operating cost per passenger as each car needs a full drive train, batteries, sensors, etc. Wouldn't using small cars increase the chance of service interruption? If a vehicle breaks down, then it blocks the tunnel. If there are 5x smaller vehicles and the breakdown rate the same then the tunnel blockage rate is 5x higher with smaller vehicles. Cars needs a minimum separation to prevent crashes in case of problems. With more cars, more of the tunnel length is reserved for separation purposes instead of carrying passengers. Regular subway cars allows people to stand, which increases passenger density. (They also let people roll on suitcases, enter using a wheelchair, push a stroller, etc., which small vehicles do not.) With the lower passenger density inherit in smaller cars mean that station platforms need to be longer and more expensive to build? How many different tunnels do you need for point-to-point service? If you want to go from A to C, do you still go through B and if so, do you need to stop while cars load/unload at B or are there bypass tunnels for each station? I looked at the channel but did not want to watch video upon video to figure out which showed small cars are more efficient.

verdverm 3y ago
You are asking questions that are based on your assumptions. These assumptions are not accurate. One example: > If you want to go from A to C, do you still go through B and if so, do you need to stop while cars load/unload at B or are there bypass tunnels for each station? You are mapping the subway architecture onto a different system. The main lines do not connect directly to the stops, rather each stop has it's own ramps. It's much more like the highway system, where there are on/off ramps at each point, it's just underground to take advantage of space in 3d rather than being limited to the 2d surface constraints.
- eesmith 3y ago
  Of course I am. But it doesn't seem worthwhile to watch unknown hours of videos to answer my question. As to the topology, sure, that's one approach. It requires many more tunnels, which is more expensive, and acceleration/deceleration lines. I've seen off-ramps fully back up to the highway lane. Why wouldn't that happen here? I've also seen people stopped in the acceleration lane waiting for a gap in traffic. If there are fewer, bigger vehicles each with more passengers then there are more gaps. So you can see why it's not clearly obvious to me that many small cars with point-to-point service is more economical.
  - verdverm 3y ago
    > which is more expensive Is it? What are you basing it on? > It requires many more tunnels Does it? What are you basing this on? Even if more tunnels, is the total volume less, are they simpler and cheaper to create because they are smaller? > I've seen off-ramps fully back up to the highway lane. Backups happen in subways, like all traffic systems. It's something you manage, not eliminate You of course skip the questions about context and the right solution for a city. They had open proposals and review periods and ended up going with the Boring tunnel system. They evaluated in detail and made the choice. If you want to understand their choice, they made it all public The big thing Boring company did was develop their own tunneling machine that is much better than the others out there. This is how they can tunnel faster and cheaper than anyone else, currently. Maybe Vegas made a mistake betting on a new way, but maybe they made a really good call. We'll have to wait and see. When you invest in large scale transportation systems, you plan for many, many decades. These point in time numbers while the system is still being built aren't evidence for success or failure.
    - eesmith 3y ago
      > What are you basing it on? My "which is more expensive" is based on having more point-to-point tunnels, rather than running single lines approximating a minimal spanning tree. The more point-to-point direct transit you have, the more tunnels you must have, which makes it more expensive. My comparison was not directly about small cars in small tunnels vs. large ones in large tunnels. > is the total volume less, are they simpler and cheaper to create because they are smaller? I don't know. You claimed it would seem to be more efficient, but in that case, why not compare a small tunnel subway like Glasgow has? 2 lines, 15 stations, 8 million ridership running on a 4 foot gauge and 11 ft width tunnels, built in the 1890s. It looks like the Vegas Loop uses 12 foot tunnels, so that should be the better head-to-head comparison, yes? > It's something you manage, not eliminate Of course, but you manage it with space, which affects the costs. Given the same number of passengers, smaller cars require more space because of the required safety distances between cars. You get the space with more tunnels and parallel tracks. > If you want to understand their choice, they made it all public If it's not easy to summarize in a few paragraphs and requires pouring over documents or watching hours of videos, then how does it seem more efficient simply by saying "a subway with smaller cars that is more point to point"? I've been to Vegas. They have lousy mass transit, the US is famously anti-public transit in part because the people who make the decisions rarely use it, and there is a long history of trying out hyped technology that doesn't work well. You'll also note that Chicago, San Jose, and LA have dropped their plans to have similar infrastructure. > We'll have to wait and see. Sure, but that's a far cry from making it seem like it's obvious given the design. And given that it's been years and the Vegas Loop has nowhere near as many passengers as the Glasgow Subway is a strong suggestion that car-based systems don't work well.
Someone 3y ago
I’m not convinced it will be more efficient for handling thousands of passengers [1], but from what I understand, this system (when operating as designed) will not stop cars inside the main tunnel, but move them to out of it into slide channels. That means a car driving from station #3 to station #33 can overtake cars at intermediate stations, passing them at full speed. One question would be whether it’s possible to write scheduling software that manages to do that well in crowded tunnels. Doing that with trains is possible, too, but would be more expensive (railroad switches are fairly high maintenance, and cause extra wear on train wheels), and scheduling train rides so that most passengers in a car stopping at a station want to go there is harder the more passengers there are in a railroad car. As to cars breaking down: they’re a lot lighter than railroad cars, so I would think that the tunnels can be designed in such a way that often, getting a broken car out of the tunnel to the nearest stop will be fairly fast, and can be done without disrupting service for long. [1] it almost certainly more efficient for handling low numbers of passengers, as moving an almost empty railway carriage takes more energy than moving a few cars. Scaling up, that advantage goes away fast, though, especially if, as is now the case, each car needs a paid driver.
- eesmith 3y ago
  > railroad switches are fairly high maintenance, and cause extra wear on train wheels Sure, but that's a tradeoff. You now have many more cars, each with its own steering system, and the components in the steering system need to be light to reduce the weight being transported.

verdverm 3y ago

You are asking questions that are based on your assumptions. These assumptions are not accurate. One example: > If you want to go from A to C, do you still go through B and if so, do you need to stop while cars load/unload at B or are there bypass tunnels for each station? You are mapping the subway architecture onto a different system. The main lines do not connect directly to the stops, rather each stop has it's own ramps. It's much more like the highway system, where there are on/off ramps at each point, it's just underground to take advantage of space in 3d rather than being limited to the 2d surface constraints.

eesmith 3y ago
Of course I am. But it doesn't seem worthwhile to watch unknown hours of videos to answer my question. As to the topology, sure, that's one approach. It requires many more tunnels, which is more expensive, and acceleration/deceleration lines. I've seen off-ramps fully back up to the highway lane. Why wouldn't that happen here? I've also seen people stopped in the acceleration lane waiting for a gap in traffic. If there are fewer, bigger vehicles each with more passengers then there are more gaps. So you can see why it's not clearly obvious to me that many small cars with point-to-point service is more economical.
- verdverm 3y ago
  > which is more expensive Is it? What are you basing it on? > It requires many more tunnels Does it? What are you basing this on? Even if more tunnels, is the total volume less, are they simpler and cheaper to create because they are smaller? > I've seen off-ramps fully back up to the highway lane. Backups happen in subways, like all traffic systems. It's something you manage, not eliminate You of course skip the questions about context and the right solution for a city. They had open proposals and review periods and ended up going with the Boring tunnel system. They evaluated in detail and made the choice. If you want to understand their choice, they made it all public The big thing Boring company did was develop their own tunneling machine that is much better than the others out there. This is how they can tunnel faster and cheaper than anyone else, currently. Maybe Vegas made a mistake betting on a new way, but maybe they made a really good call. We'll have to wait and see. When you invest in large scale transportation systems, you plan for many, many decades. These point in time numbers while the system is still being built aren't evidence for success or failure.
  - eesmith 3y ago
    > What are you basing it on? My "which is more expensive" is based on having more point-to-point tunnels, rather than running single lines approximating a minimal spanning tree. The more point-to-point direct transit you have, the more tunnels you must have, which makes it more expensive. My comparison was not directly about small cars in small tunnels vs. large ones in large tunnels. > is the total volume less, are they simpler and cheaper to create because they are smaller? I don't know. You claimed it would seem to be more efficient, but in that case, why not compare a small tunnel subway like Glasgow has? 2 lines, 15 stations, 8 million ridership running on a 4 foot gauge and 11 ft width tunnels, built in the 1890s. It looks like the Vegas Loop uses 12 foot tunnels, so that should be the better head-to-head comparison, yes? > It's something you manage, not eliminate Of course, but you manage it with space, which affects the costs. Given the same number of passengers, smaller cars require more space because of the required safety distances between cars. You get the space with more tunnels and parallel tracks. > If you want to understand their choice, they made it all public If it's not easy to summarize in a few paragraphs and requires pouring over documents or watching hours of videos, then how does it seem more efficient simply by saying "a subway with smaller cars that is more point to point"? I've been to Vegas. They have lousy mass transit, the US is famously anti-public transit in part because the people who make the decisions rarely use it, and there is a long history of trying out hyped technology that doesn't work well. You'll also note that Chicago, San Jose, and LA have dropped their plans to have similar infrastructure. > We'll have to wait and see. Sure, but that's a far cry from making it seem like it's obvious given the design. And given that it's been years and the Vegas Loop has nowhere near as many passengers as the Glasgow Subway is a strong suggestion that car-based systems don't work well.

Someone 3y ago

I’m not convinced it will be more efficient for handling thousands of passengers [1], but from what I understand, this system (when operating as designed) will not stop cars inside the main tunnel, but move them to out of it into slide channels. That means a car driving from station #3 to station #33 can overtake cars at intermediate stations, passing them at full speed. One question would be whether it’s possible to write scheduling software that manages to do that well in crowded tunnels. Doing that with trains is possible, too, but would be more expensive (railroad switches are fairly high maintenance, and cause extra wear on train wheels), and scheduling train rides so that most passengers in a car stopping at a station want to go there is harder the more passengers there are in a railroad car. As to cars breaking down: they’re a lot lighter than railroad cars, so I would think that the tunnels can be designed in such a way that often, getting a broken car out of the tunnel to the nearest stop will be fairly fast, and can be done without disrupting service for long. [1] it almost certainly more efficient for handling low numbers of passengers, as moving an almost empty railway carriage takes more energy than moving a few cars. Scaling up, that advantage goes away fast, though, especially if, as is now the case, each car needs a paid driver.

eesmith 3y ago
> railroad switches are fairly high maintenance, and cause extra wear on train wheels Sure, but that's a tradeoff. You now have many more cars, each with its own steering system, and the components in the steering system need to be light to reduce the weight being transported.