The Boring Company FAQ • Hacker News Board

Re: The Boring Company FAQ

#221

Post by kuschku » Wed, May 17, 2017, 7:41 AM UTC

tomjakubowski wrote: post #172

objclxt wrote: post #132

Earlier quoted context omitted.

> So, $100M per mile with Upkeep Lite™ sounds good when making conversation about the topic. Also the $1B/mile is the cost of the Purple Line extension in Los Angeles. Worst case cost no doubt. A real figure nevertheless. The figure is way out. Crossrail in London has a $20 billion total budget (£15b GBP), with 26 miles of tunnel[1]. But the tunnel is only part of the project, several billion is being spent on new re…

I don't know where this "$1B/mile" just for tunneling figure comes from. That's certainly not the tunneling cost for any current subway extension project in Los Angeles: all-in (i.e. not only tunneling) estimates for the first phase of the Purple Line extension are at $2.8B for 3.9 miles of heavy rail subway; the full Purple Line Extension is estimated at $6.3B for 9 miles of heavy rail subway. The closest thing is t…

In one of the subway projects in Hamburg, a cost of 1.1 billion EUR per kilometre was reached.

But that project was building a subway including station directly below a riverbed.

Re: The Boring Company FAQ

#222

Post by yladiz » Wed, May 17, 2017, 7:42 AM UTC

yongjik wrote: post #126

sien wrote: post #118

Earlier quoted context omitted.

Also by going underground. Tokyo's metro is fantastic and one of the few globally that has more than 100% farebox recover ratio. https://en.wikipedia.org/wiki/Farebox_recovery_ratio#Farebox...

> more than 100% farebox recover ratio Doesn't this just mean that they are expensive? I heard complaints about how expensive Tokyo's subway is. Reducing price and propping the system with tax can be a better approach in the long term, because that can encourage more people to use public transit and reduce demand for costly highways. (Also, one could argue that the freedom to move around at an affordable price is a b…

It's hard to say, because there's a few different subway operators in Tokyo, and if you switch between them your fare doesn't transfer. An example is JR and Tokyo Metro. There also exists Tobu lines, which run on Tokyo Metro lines, but sometimes have a different schedule. In my experience, the base fare (the price of entry) seems a little high, but the price stays the same for the first few stops, meaning that going 2 stops is more expensive than 4 stops. I think this effect continues into longer subway lines, and the prices of going to different stations is staggered if they are close together (e.g. if two stations are close enough, the price will be the same to go to if you come from the same location). I would argue that Tokyo's subway, overall, is probably about the same price if Bart was the same size.

Beyond the price, Tokyo Metro is almost always on time and pretty clean, and generally the delays happen late at night (the delays are only for a minute or two). Having been here for over a month, I've only experienced one daytime delay that lasted more than 30 seconds.

Re: The Boring Company FAQ

#223

Post by falsedan » Wed, May 17, 2017, 7:42 AM UTC

Cthulhu_ wrote: post #208

picosat wrote: post #184

Earlier quoted context omitted.

The American obsession with "alone time" is exactly why Musk's idea is the only effective way to relieve the traffic problem. Americans are adverse to change, and the result of this is a solution needs to leverage our existing infrastructure. Putting the cars on sleds allows people to keep the luxury and flexibility of personal cars without requiring a lifestyle shift. Furthermore, a solution that leverages personal…

> Americans are adverse to change I don't get it, where does that come from anyway? I mean America's mostly a country of immigrants; most inhabitants' forefathers, only a couple generations ago, abandoned everything they know to build up a new life. If that's not change, then IDK what is. I think that at one point it's not about what they want - having the option even to drive anywhere is a luxury a lot of people don…

> I don't get it, where does that come from anyway?

Let's:

* replace tipping with a minimum wage which helping working people get out of poverty

* make checks obsolete

* etc.

> Driving in New York isn't practical, so people take the tube

The what now? I think you'll find it's actually called le Métropolitain

Re: The Boring Company FAQ

#224

Post by kuschku » Wed, May 17, 2017, 7:43 AM UTC

Tomminn wrote: post #174

erentz wrote: post #74

Earlier quoted context omitted.

Yeah this is all very odd and everyone is lapping it up. He claims to want to reduce tunneling costs by a factor of 10, but starts by quoting a very high benchmark of $1 billion per mile which is quite easy to beat. Then he reduces diameters to something much smaller than all the expensive mega projects, into the range of something where technology is well established and costs are already 1/10th of his quoted $1 bil…

I think the sled idea is really interesting. Imagine a conveyor belt like you have in airports. Except it moves cars at 150 mph through an underground tunnel instead of people at 15mph. Traffic is often massively asymmetric so you can just reverse the direction it travels at noon. It seems plausible that keeping a conveyor belt in good service is cheaper than keeping a fleet of railway cars is. It's also significantl…

The throughput of "car directly after car" is about 10 times lower than that of a railway with a frequency of 90 seconds.

Re: The Boring Company FAQ

#225

Post by factsaresacred » Wed, May 17, 2017, 7:44 AM UTC

djsumdog wrote: post #151

prostoalex wrote: post #131

Earlier quoted context omitted.

> But then for some reason the solution has to involve putting cars into these tunnels. If what he thinks he is on to is viable with cars in those tunnels, it's even more viable with trains carrying 1,000 passengers each coming every 3 minutes. So why aren't we building these subways with trains? Because with trains you never build just a tunnel - there are train stations, escalators leading in and out, ticketing boo…

But even with the stations, escalators and everything else, you're talking about orders of magnitude between trains and cars. London during peak hour has trains arriving less than 1 min 30 sec apart. They move an absolutely insane amount of people. Singapore's trains are entirely automated and arrive at Everything about Musk's idea seems absolutely terrible. If America had better trains and subways, it could move mas…

> Everything about Musk's idea seems absolutely terrible.

Depends what his goal is. Currently getting from A to B in a car at a certain time involves traffic jams.

If his goal is to get from A to B most efficiently in a car then it's one of the best ideas.

If his goal is get people from A to B via any mode of transport, perhaps trains. But he owns a car company, so that's not exactly in his interest.

Also with cars it's truly A to B. Not A to subway/carpark, wait, travel, walk to B.

Re: The Boring Company FAQ

#226

Post by yladiz » Wed, May 17, 2017, 7:45 AM UTC

chronic940 wrote: post #144

yongjik wrote: post #126

Earlier quoted context omitted.

> more than 100% farebox recover ratio Doesn't this just mean that they are expensive? I heard complaints about how expensive Tokyo's subway is. Reducing price and propping the system with tax can be a better approach in the long term, because that can encourage more people to use public transit and reduce demand for costly highways. (Also, one could argue that the freedom to move around at an affordable price is a b…

For those wondering, it costs 4-5 USD one way.

It only costs that much if you're staying far away or going pretty long distances. I stay in a station pretty far from Central Tokyo (past Kita Senju on the Tobu line) and to get to somewhere like Ginza costs less than 400 Yen, which is about $3.75. However, a chunk of that cost is due to Tobu, and if I was staying in Kita Senju or Ueno my trip would only be about 200-250 Yen.

Re: The Boring Company FAQ

#227

Post by bamboozled » Wed, May 17, 2017, 7:47 AM UTC

erentz wrote: post #74

Animats wrote: post #61

So, the key ideas are: - Smaller diameter tunnels. 14' is suggested. This is slightly larger than the deep London Tube lines. - Electrically powered TBMs. Those exist. However, often the business end of the machine is hydraulically powered. Musk is probably thinking of going all electric, at least for the cutter head. After all, he has lots of experience with high-torque electric motors. - Do cutting and tunnel ring…

Yeah this is all very odd and everyone is lapping it up. He claims to want to reduce tunneling costs by a factor of 10, but starts by quoting a very high benchmark of $1 billion per mile which is quite easy to beat. Then he reduces diameters to something much smaller than all the expensive mega projects, into the range of something where technology is well established and costs are already 1/10th of his quoted $1 bil…

"If what he thinks he is on to is viable with cars in those tunnels, it's even more viable with trains carrying 1,000 passengers each coming every 3 minutes"

When it's all said and done, Elon is a car salesman and entrepreneur, I guess that's why?

Re: The Boring Company FAQ

#228

Post by SargoDarya » Wed, May 17, 2017, 7:50 AM UTC

factsaresacred wrote: post #225

djsumdog wrote: post #151

Earlier quoted context omitted.

But even with the stations, escalators and everything else, you're talking about orders of magnitude between trains and cars. London during peak hour has trains arriving less than 1 min 30 sec apart. They move an absolutely insane amount of people. Singapore's trains are entirely automated and arrive at Everything about Musk's idea seems absolutely terrible. If America had better trains and subways, it could move mas…

> Everything about Musk's idea seems absolutely terrible. Depends what his goal is. Currently getting from A to B in a car at a certain time involves traffic jams. If his goal is to get from A to B most efficiently in a car then it's one of the best ideas. If his goal is get people from A to B via any mode of transport, perhaps trains. But he owns a car company, so that's not exactly in his interest. Also with cars i…

I think you guys all forget the point that it's not only for cars but also for cargo which makes this a lot better.

Re: The Boring Company FAQ

#229

Post by dredmorbius » Wed, May 17, 2017, 7:54 AM UTC

Baeocystin wrote: post #128

dredmorbius wrote: post #102

Earlier quoted context omitted.

It turns out that most transportation tunnels do in fact have a significant input of energy. Ventillation to exhaust waste heat is a major concern. From discussions of net-zero housing in Alaska (Thorstein Chlupp), my understanding is that water tends to flow from hot to cold -- it will condense along a cold surface. A condenser + sump system where some engineering mechanism keeps the inner tunnel wall from remaining…

While you're right, in that heat is an issue in tunnels, harvesting low-temperature-delta energy is incredibly inefficient. It is always better to source the needed electricity from a generator that is specifically designed for such. (The only time this may be untrue is when dealing with very small things like remote sensors, where running a wire might actually be more expensive than harvesting the microwatts needed…

What I'm saying is that for the purposes of removing moisture, the temperature gradient itself is an energy flux which might be utilised.

In some ways, this is the inverse of an evaporative cooler, where the incoming air is saturated with moisture to lower its temperature before being vented to a warm space to be cooled ("swamp coolers" are best suited to dry climates, and have humidity issues). Here, instead, cool (possibly chilled) air could be ducted through the warm space, with the intent of condensing moisture onto the ductwork (for drainage by other means) prior to being vented into the space.

You're trading cooling capacity (condensing water warms the cold air supply) for humidity control.

I'm not trying to imply that this is practical, only that a latent energy flux might exist.

Re: The Boring Company FAQ

#230

Post by ktta » Wed, May 17, 2017, 7:56 AM UTC

gfodor wrote: post #198

ktta wrote: post #127

Earlier quoted context omitted.

(If you're taking about inter-city travel) I really doubt one person on a lane can be faster than a freeway with 4+ lanes (in one direction) no matter how fast it is going. Another thing you'll have to consider is that there will be a logistical problem at the exit stops if you want to take advantage of all the high speeds being talking about. I'm talking about passengers getting stopped off there. There have to be a…

Presumably we would get better at building more tunnels after the first one, and presumably once an existence proof is in place the economics will justify accelerated R&D, resulting in a technological feedback loop. You can only layer so many roads above ground. But as said in the post, tunnels have no such limit. 100 years from now one could imagine a very thick subterranean transportation network. The interchange a…

Tunnels might look more futuristic, but I can't imagine a world where building layers of tunnels will be cheaper than larger roads.

We've already put the R&D into roads, and the cars that run on them. Routing problems have also been solved. No matter that feedback loop, it wouldn't get cheaper than laying a road.

It's true that you can build many tunnels, but why? Congestion is really a problem in inner city roads. I rarely hear of any congestion in freeways, and I have to say, expanding to a couple more lanes sounds a lot more viable.