Comment by trainmew | Hacker News Reader

Comment by trainmew | Hacker News Reader

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> It's cheaper.

Not convinced.

> expensive train stuff

Sure, I'll concede it can be cheaper than subways when you remove the tracks, HV power supply, third rail, wayside equipment, stations and just stick to concrete.

I still don't think they're significantly more expensive.

> A string (even a long one) of high-intensity LED lights doesn't require much electricity. The costs of lighting the tunnel is probably one of the least costly parts of this whole project.

Maybe. You will still need redundant power supply and redundant illumination points if you're planning to use the self-driving tech with cameras.

> then it won't be difficult to have the vehicles talk to each other (or a centralized hub)

So then you will need a way for those cars to talk to each other, and typically that means you will need wayside APs to carry that traffic. Now that tunnel is not just bare concrete and some lighting elements, you will need to lay fibre cables, power cables, and put up those boxes somewhere for communication. And oh, you might want to have calibration points on the tunnel floor so that the skates themselves know where they are, to normalize their position and report back true accurate positioning.

> The vehicles being able to know how to get to the station and open their doors is probably not really a concern. This is already done in automated subway systems all over the world. It's not hard to have the vehicle be smart enough to drive to a specific 'dock' and then look for a specific trigger to know when to open its doors. Hell, my $100 roomba can park itself in a similar manner.

You underestimate the amount of engineering work needed to do this safely and proving that it's safe. Are the lifts open lifts where the skates drive on and open up their doors? If so, that "marker" will need to be substantially big to allow for overshoot/undershoot and still be safe to open their doors (think, pinching, trapping, etc).

If so, the lifts will need to be substantially big to allow for a number of these skates to ascend and pick up/drop off passengers.

You seem to be really hung up on the ability of the skates to know where they are. I'm not sure why.

There's no indication that the skates would rely on lighting whatsoever to be able to function. Existing cars on the market already ship with sonic- or LIDAR-based cameras that can detect obstructions in complete darkness. Tesla's existing autopilot functionality works just fine on dark unlit roads.

>So then you will need a way for those cars to talk to each other, and typically that means you will need wayside APs to carry that traffic.

You've never heard of a mesh network? Even if AP are needed, it's still considerably less wiring than a full third rail setup and still poses no fire risk.

>And oh, you might want to have calibration points on the tunnel floor so that the skates themselves know where they are, to normalize their position and report back true accurate positioning.

This could literally be something as simple as a handful of RFID tags on the floor of the tunnel. Not costly and not hard to implement.

>You underestimate the amount of engineering work needed to do this safely and proving that it's safe. Are the lifts open lifts where the skates drive on and open up their doors? If so, that "marker" will need to be substantially big to allow for overshoot/undershoot and still be safe to open their doors (think, pinching, trapping, etc).

>If so, the lifts will need to be substantially big to allow for a number of these skates to ascend and pick up/drop off passengers.

You're really overestimating the amount of engineering work needed to be done. Again, my $100 roomba is able to park itself within millimeters onto a dock, and it's never had an issue. Automated subway systems all over Asia also operate with only inches of margin for positioning themselves onto station platforms and aligning their doors, and they don't seem to have an issue.

The concerns you're raising are already solved. The 'magic' of this system isn't in the self-driving vehicles part at all, as that's already being done with automated transport systems the world over. The 'magic' is in the tunnel construction itself.

> You seem to be really hung up on the ability of the skates to know where they are. I'm not sure why.

Because the claim is that the tunnels are nothing more than concrete and some lighting. I'm pointing out instances that will require more things in these tunnels.

> You've never heard of a mesh network? Even if AP are needed, it's still considerably less wiring than a full third rail setup and still poses no fire risk.

Yes, I know mesh networks. This is how many trains now communicate with each other. Third rail has some fire risk (incredible odds, however, and likely means maintenance regime is not good), and I agree that if they are removed that removes the fire hazard entirely. However, these skates carry batteries, hundreds of them and operating at significantly high speeds. I'm pointing out that these batteries can and will catch fire too, especially if the self-driving component of the skates fail. It is a more credible risk (but cheaper, sure) and more likely to happen more frequently given that the self-driving component is not perfect and relies on cameras (even LIDAR ones) than third rail catching fire.

> You're really overestimating the amount of engineering work needed to be done.

I'm really not. I work on those automated subway systems in Asia that has automated platform gates for those subways to stop at, and the amount of engineering and safety assurance work to ensure those trains actually align themselves correctly is a lot. Why do you think those platform gates have emergency egress doors all over? Have you ever noticed those trains stopping, then creeping to ensure they're aligned right? Those issues are not there not because they're easy, but because substantial man-hours of work have been done to ensure they are safe.

> The concerns you're raising are already solved. The 'magic' of this system isn't in the self-driving vehicles part at all, as that's already being done with automated transport systems the world over. The 'magic' is in the tunnel construction itself.

And I'm pointing out that there's no magic in the tunnel construction. By the time you have added those safety redundancies you end up with something very close to a subway system, just with smaller carriages running on batteries.

>And I'm pointing out that there's no magic in the tunnel construction. By the time you have added those safety redundancies you end up with something very close to a subway system, just with smaller carriages running on batteries.

What safety redundancies? You still haven't pointed out any required safety redundancies that would raise the cost of the tunnel any significant amount. Some RFID tags and low voltage wiring and fiber for a couple of wireless access points is still negligible cost compared to a full blown track-and-third-rail system. Your entire argument rests on "what if the cars aren't good at self-driving", but again, we already have vehicles with these technologies on the market that drive thousands of miles a day without issue. Tesla cars drive on autopilot on completely dark, unlit roads all the time without issue. They park themselves in tight parking spots every day without issue. They avoid collisions with other vehicles at high speeds every day without issue.

I'm no fan of Tesla, and I'll be the first person telling you that they fucked up bigtime handling the crash a few months ago, but that still doesn't change the fact that they have existing autopilot systems that are more than capable of handling this 'Dugout Loop' system.

As for your skepticism that the tunnels will be cheaper, go do some research on how expensive it is to build out subway tunnels and the components of those costs. The Dugout Loop system eschews significant amounts of the major cost components.

If you're skeptical because we're talking about Musk and his penchant for cost overruns and missed deadlines, I'd understand. But if you're skeptical because for some reason you don't think a barebones concrete tunnel (even with some additional wiring and networking components) is cheaper than a full blown subway tunnel and station, that's just because you're being stubborn.

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