Elon Musk Unveils Boring Co's First Tunnel • Hacker News Board

Re: Elon Musk Unveils Boring Co's First Tunnel

#231

Post by jillesvangurp » Thu, Dec 20, 2018, 8:34 AM UTC

xvilka wrote: post #134

jillesvangurp wrote: post #130

Earlier quoted context omitted.

Tunneling is currently so expensive that there are few companies doing any innovation on how to properly utilize them. A big part of the problem is actually digging them in a way that is cheap and scaleable. Another part of the problem is the organizations doing the digging and doing the exploitation are typically have misaligned incentives and goals. For example, expanding subway systems is currently in the hands of…

Apart from pointing at Asian nations building subways in almost every big city, it might also worth a look to the Arab Peninsula, with also very high speed of digging and building required infrastructure. It is only US who is behind at this sadly.

This is a problem in Europe as well. The new North south line in Amsterdam cost over 3 Billion to complete and took well over a decade to build.

China is indeed digging at huge speed.

My understanding with the Boring company is not that they are doing anything particularly special but merely doing things in a way that facilitates economies of scale. So, they standardize designs, equipment, logistics, etc. and they use automation. If you do a one off tunnel with a machine that will only be used for that tunnel, that doesn't make sense. If you are planning to do many tunnels that makes a lot of sense.

Re: Elon Musk Unveils Boring Co's First Tunnel

#232

Post by dmitriid » Thu, Dec 20, 2018, 9:06 AM UTC

reissbaker wrote: post #215

Tiktaalik wrote: post #194

Earlier quoted context omitted.

haha yep. This plan is like when a city widens a highway but doesn't touch other parts of the road network? What happens? It just moves the choke point somewhere else in the network.

Agreed 1s gaps are too tiny — seems unsafe and that'd be a lot of elevator traffic. 5s seems doable though: assuming 5s gaps, you need an elevator system capable of moving one car every 5s, and then the tunnel is optimally saturated. That doesn't seem insurmountably hard: two elevators that take 10s each to go from surface to tunnel would be enough, along with a bit of on-ramp tunnel to allow cars to accelerate to sp…

You're assuming you can get cars into the elevators at 5s intervals.

Almost all assumtions in the discussion start directly in the tunnel, and sometimes at the elevator. Almost no one thinks about: how will cars get into that thing from the road, how the cars will get out of that thing onto the road.

Re: Elon Musk Unveils Boring Co's First Tunnel

#233

Post by reissbaker » Thu, Dec 20, 2018, 9:37 AM UTC

dmitriid wrote: post #232

reissbaker wrote: post #215

Earlier quoted context omitted.

Agreed 1s gaps are too tiny — seems unsafe and that'd be a lot of elevator traffic. 5s seems doable though: assuming 5s gaps, you need an elevator system capable of moving one car every 5s, and then the tunnel is optimally saturated. That doesn't seem insurmountably hard: two elevators that take 10s each to go from surface to tunnel would be enough, along with a bit of on-ramp tunnel to allow cars to accelerate to sp…

You're assuming you can get cars into the elevators at 5s intervals. Almost all assumtions in the discussion start directly in the tunnel, and sometimes at the elevator. Almost no one thinks about: how will cars get into that thing from the road, how the cars will get out of that thing onto the road.

Presumably they'd drive into the elevator on one side, and drive out of the elevator on the other side.

Re: Elon Musk Unveils Boring Co's First Tunnel

#234

Post by beobab » Thu, Dec 20, 2018, 9:59 AM UTC

noobermin wrote: post #79

beobab wrote: post #74

Earlier quoted context omitted.

Why not both? He's got money to spend.

He's free to do whatever. Governments shouldn't shell out money to give to him because his solution isn't one.

Why not? If he can convince a government panel that he can give them some value for their money, then it makes sense to "shell out money" (very persuasive language there - I approve) to him.

It's not free money. He has to give some value back.

Re: Elon Musk Unveils Boring Co's First Tunnel

#235

Post by kurtisc » Thu, Dec 20, 2018, 11:09 AM UTC

grecy wrote: post #212

kurtisc wrote: post #211

Earlier quoted context omitted.

I've not seen anything that would suggest either ratio.

So what's your guess?

It would be just that, a guess, and a particularly bad one since I'm not in the US anyway.

Re: Elon Musk Unveils Boring Co's First Tunnel

#236

Post by dmitriid » Thu, Dec 20, 2018, 12:55 PM UTC

reissbaker wrote: post #233

dmitriid wrote: post #232

Earlier quoted context omitted.

You're assuming you can get cars into the elevators at 5s intervals. Almost all assumtions in the discussion start directly in the tunnel, and sometimes at the elevator. Almost no one thinks about: how will cars get into that thing from the road, how the cars will get out of that thing onto the road.

Presumably they'd drive into the elevator on one side, and drive out of the elevator on the other side.

Even if you have a separate elevator for entry and a separate eleveotr for exit: how do you get to a 5s interval?

Re: Elon Musk Unveils Boring Co's First Tunnel

#237

Post by Skye » Thu, Dec 20, 2018, 3:51 PM UTC

xvilka wrote: post #226

Skye wrote: post #189

Earlier quoted context omitted.

IIRC the main heat source is the breaking of the trains combined with the high frequency of them. I suspect that using many cars will still release a lot of heat into the tunnels.

Yes, with a small gap between it is harder to install proper cooling systems and also natural air movement it very limited for cooling purpose too.

The trains in the narrow tunnels push air around, so recent stuff like full height platform screen doors help improve conditions (allowing platforms to be air conditioned without having to air condition the tunnels)