[trainmew]

> fire suppression systems

The article clearly states the tunnels with have a tunnel ventilation system, which is standard fire suppression strategy for underground tunnels for subways.

> electrical systems

They're already laying power cables for the tunnel lighting system which is presumably for their autonomous driving system with cameras, which now has a single dependency on their tunnel lighting system.

The rest, sure, I agree can be cheaper comparatively to a subway tunnel.

> steep inclines/sharper angles

Why would you want steep inclines (more than 5% standard for metros) if you're already underground and use lifts to ascend? The electric skates will still have a kinematic envelope that the tunnel has to adhere to, especially if they're for standing passengers. I don't see how this differs substantially from subway tunnels to allow steeper inclines/sharper angles.

[txcwpalpha]

>The article clearly states the tunnels with have a tunnel ventilation system, which is standard fire suppression strategy for underground tunnels for subways.

Standard subway systems have to have much more in regards to fire suppression than just ventilation. The entire tunnel has to be protected from fire damage with insulation, some tunnels have sprinkler systems, etc. These wouldn't be needed in the dugout tunnel.

>They're already laying power cables for the tunnel lighting system which is presumably for their autonomous driving system with cameras, which now has a single dependency on their tunnel lighting system.

A power cable for low-voltage lighting is much, much, much different than the electrical systems required for powering a subway train. It's like the difference of running an extension cord to your lamp versus laying mains wiring for an entire house.

There's also no reason to believe that the vehicles would be dependent on the lighting system. Many cars on the market today already come with sonic- or LIDAR-based cameras that do not need lamps to detect obstructions. Tesla's own autopilot on its cars works just fine on unlit roads. There are also automated subway systems all over the world that don't depend on the tunnels being lit, and they don't seem to have any issue avoiding collisions.

>Why would you want steep inclines (more than 5% standard for metros) if you're already underground and use lifts to ascend? The electric skates will still have a kinematic envelope that the tunnel has to adhere to, especially if they're for standing passengers. I don't see how this differs substantially from subway tunnels to allow steeper inclines/sharper angles.

You wouldn't want them, but not being bound to the grade and angle restrictions of a tracked metro train means that you have more flexibility of where your system can go if you need to. It makes it easier to route around existing tunnels, piping, sewers, etc without having to make huge detours or being forced to use elevators.

An example of this is given in the linked website where they talk about the eastern terminus of the tunnel - it uses a ramp (from the looks of it, a ramp with a steepness that a subway train would never be able to use). If space allows for such a ramp, it's probably cheaper than using an elevator.

[trainmew]

> Standard subway systems have to have much more in regards to fire suppression than just ventilation. The entire tunnel has to be protected from fire damage with insulation, some tunnels have sprinkler systems, etc. These wouldn't be needed in the dugout tunnel.

No they don't. There's no insulation for underground tunnels for subways; just steel liners and reinforced concrete, at least according to NFPA 130. No sprinkler systems. So no difference here.

> LV vs HV

Yes, true. HV cables and other supporting systems are more expensive. So the only difference here is batteries, which are far more combustible than cables in concrete.

> LIDAR cameras

Correct me if I'm wrong, but to my knowledge, Tesla has removed LIDAR-based cameras in their lineup.

> There are also automated subway systems all over the world that don't depend on the tunnels being lit, and they don't seem to have any issue avoiding collisions.

Yes, I know. And those trains communicate via access points placed on the tracks, each of which are run with fibre and power cables. Now that bare tunnel is no longer bare.

> incline

Sure, it's more flexible. It still doesn't address the claim that this will help make those tunnels cheaper.

[txcwpalpha]

>No they don't. There's no insulation for underground tunnels for subways; just steel liners and reinforced concrete, at least according to NFPA 130. No sprinkler systems. So no difference here.

Not sure where you're getting that info. I just looked up NFPA 130 and it specifically calls for multiple types of insulation (for cables as well as concrete and steel) as well as automated water sprinkler systems, and even standpipes for firefighters.

>Correct me if I'm wrong, but to my knowledge, Tesla has removed LIDAR-based cameras in their lineup.

Tesla doesn't use LIDAR but they do use ultrasonic sensors. Tesla's existing autopilot systems works just fine on completely dark, unlit roads. I don't see why these skates would be any different.

>Yes, I know. And those trains communicate via access points placed on the tracks, each of which are run with fibre and power cables. Now that bare tunnel is no longer bare.

Even with fibre and low voltage power for access points (if even needed), you're still leagues away from the cost and complexity of a full tracked third-rail system.

>Sure, it's more flexible. It still doesn't address the claim that this will help make those tunnels cheaper.

I'm not sure what you mean. Flexibility is cheaper. Being able to use a tunnel that is 500 feet long at a 10% grade is cheaper than having to build a tunnel that is 1500 feet long at 3% grade.

[trainmew]

> Not sure where you're getting that info. I just looked up NFPA 130 and it specifically calls for multiple types of insulation (for cables as well as concrete and steel) as well as automated water sprinkler systems, and even standpipes for firefighters.

You're moving the goalpost and earlier insinuated that tunnels for subways require lining and other fire suppression systems. They do not. The automated sprinklers are needed for stations, but not the tunnel itself. Same for standpipes.

The insulation for cables are a given, because you will need it for ALL tunnels. Not just HV cables, but ALL cables, including fibre and low-voltage cables.

Thus, no difference.

> Tesla doesn't use LIDAR but they do use ultrasonic sensors. Tesla's existing autopilot systems works just fine on completely dark, unlit roads. I don't see why these skates would be any different.

Does Tesla's existing autopilot system using LIDAR/ultrasonic cameras have automated collision protection that does so without having to communicate with the other cars behind it traveling at 120mph to 150mph? No. You will need to modify the system to do this, and you will need to add the mesh network to the tunnels, among other things I described.

> Even with fibre and low voltage power for access points (if even needed), you're still leagues away from the cost and complexity of a full tracked third-rail system.

Agreed. Tracks and third rail are not cheap, comparative to not using them at all.

> I'm not sure what you mean. Flexibility is cheaper. Being able to use a tunnel that is 500 feet long at a 10% grade is cheaper than having to build a tunnel that is 1500 feet long at 3% grade.

How? If the total length of the overall tunnel is the same, the cost of materials are not substantially different.

[txcwpalpha]

>You're moving the goalpost and earlier insinuated that tunnels for subways require lining and other fire suppression systems. They do not. The automated sprinklers are needed for stations, but not the tunnel itself. Same for standpipes.

I haven't moved the goalposts whatsoever. My original comment, which you replied, to, specifically said that a significant part of the cost savings of this project involves the differences in station construction. Stations have always been part of the discussion.

I think you may be confused by the terminology. "Tunnel" does not mean only the trackway where trains travel. Subway stations can also be part of the "tunnel". This is why in my earlier comment I specifically said that "some tunnels require water sprinklers" - because the tunnel parts that are stations require them, even though the tunnel parts that are trackway do not.

>The insulation for cables are a given, because you will need it for ALL tunnels. Not just HV cables, but ALL cables, including fibre and low-voltage cables.

Sure, and the fact that you need significantly less cabling for this tunnel means that you will save on having to insulate those cables.

>Does Tesla's existing autopilot system using LIDAR/ultrasonic cameras have automated collision protection that does so without having to communicate with the other cars behind it traveling at 120mph to 150mph?

Yes? I'm not sure what the point of this question is. Tesla's current autopilot functions every day relying only on cameras and no communication with surrounding vehicles. If anything, the fact that you're removing the variability of cars on the road and will only be interacting with other skates makes this less of a problem.

>How? If the total length of the overall tunnel is the same, the cost of materials are not substantially different.

The total length of the tunnel isn't the same. In my above example, 500 ft vs 1500 ft.