Hacker News new | past | comments | ask | show | jobs | submit login
The Boring Company FAQ (boringcompany.com)
624 points by schiffern on May 17, 2017 | hide | past | web | favorite | 451 comments

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 assembly simultaneously. Some TBMs already do that. Those exist; they're called double-shielded TBMs.

Issues glossed over:

- Soil variability. Very different techniques are required for different soils. Sometimes the soil has to be "conditioned", adding something to make it solid enough it can be drilled through.[1] This is the biggest practical problem in tunneling. Too much water is the usual problem.

- The back end. TBMs are long machines. The front end does cutting and ring assembly. The back end, which can be several hundred feet long, is mostly material handling. There's usually a two-track narrow gauge railroad behind the TBM, carrying ring segments forward and dirt backwards. It's constantly being extended with new track sections. That's part of the TBM's job.

Here's a good overview of TBMs design, from Machine Design.[2]

[1] http://www.therobbinscompany.com/wp-content/uploads/2014/08/... [2] http://www.machinedesign.com/archive/art-digging-hole

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 billion per mile. 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?

The largest part of the problem to solve here for the US is not the technology of tunneling. It's the process of engineering and building infrastructure like this that seems to become way more expensive in the US compared to places like Spain. I do believe he could reduce costs by vertically integrating the whole thing. But then we should ask why don't we do that anyway?

> But then we should ask why don't we do that anyway?

Sure. Why didn't we have electric cars before tesla? Why didn't Boeing or Lockheed Martin make reusable rockets?

Alan Kay said something[1] recently that has been bouncing around my head for the past few days. He said that many people think darwinian processes (like the economy) optimize. "One my degrees is in molecular biology, and I can tell you, any biologist would say they're absolutely not optimized. The whole point is to fit into some niche in an environment. And if the environment isn't the right kind of environment evolution isn't going to give you something interesting".

In the context of the economy, if there's no innovation, and not enough competition, and no new players entering a market, I don't think its all that surprising that the existing companies might stop reaching to be more efficient.

It seems strange to think that companies would leave money on the table, but in older industries I think this is exactly what happens. The money just requires too much organizational churn for their corporate appetite.

[1] https://youtu.be/DIR6Rmhm3To?t=54m17s

You nailed it on the head. "It seems strange to think that companies would leave money on the table, but in older industries I think this is exactly what happens. The money just requires too much organizational churn for their corporate appetite." As companies grow, they get filled with layers of middle management to handle organizational complexity but this is one of the biggest costs centers. Additionally, as time goes by, these are the jobs that are looked at during cuts so everyone in this layer is in self preservation mode. They start hoarding information going up and down to make themselves indispensable and slowly the organization becomes the Titantic and can't get out of their own way.

Off topic:

The more I think about organizations the more I they seem to be the key players preventing change to me. (Which is not necessarily a bad thing)

Business says: We had this great idea, now let's freeze everything in time and let's make money of this snapshot forever, because who knows when we'll find gold again.

Entertainment industry likes to do that especially.

That's not businesses - that's humans. Or do you apply for a new job every two weeks whenever you see a higher salary advertised?

The assumption there is that higher salary is the #1 consideration. My metric is a blend of salary, lifestyle, and risk.

More precisely it's humans when they form a bunch / organization ;).

NO, I'm saying that even individuals are conservative in that they will tend to stay with an existing job, locale or speciality even when an alternative could potentially offer better returns. I don't check the job listings every day.

Risk vs reward. Often the risk is too great, especially for a company that is making a lot of money. Why risk R&D when there's no competitor. Companies are optimised to make money, not progress.

The phrase "exploitation versus exploration" seems appropriate here.

In my opinion autonomy is key. Big organizations like to talk a big game that they empower their employees to take risks. Yet most of the time they default to the status quo. It's culturally there or not.

Exactly. Also they become fat over time shifting the reality of costs.

I think both the 'people' Kay refers to and Kay himself are right. It just depends on the scale you're looking at.

Darwinian processes are near-perfectly optimized ... for an extremely local maximum. Once there, they fail to make jumps to much better nearby maxima.

If you look at a somewhat larger scale, where there are better maxima available, then the correct conclusion is that they are absolutely not optimized.

Wouldn't Darwinian processes produce "just barely good enough" solutions? i.e. once you're at the stage where things are good enough to survive long enough to reproduce, evolution doesn't play much of a role.

A great example of this is me; I'm pretty amazing; I can move around my environment, make a living to a sufficient degree to cover costs of food and shelter, and somehow even have a fiancée and manage to keep another organism alive & fed. However I'm not an expert at everything, I'm pretty bad at most sporting based things (even compared to other, existing humans; not some theoretical concept of perfection), and I spend about a third of my life doing nothing (sleeping), despite this not necessarily being required (e.g. Dolphins can sleep half their brain at a time, allowing them to avoid this inefficient downtime).

Yup. Until there's selection pressure working against you once again. Imagine if society broke down completely, so you had to fight for the limited amount of food that was available?

Somewhat related: it was interesting when my kids were born; they both had to be C-sectioned. I asked the obstetrician about it, and yes, bigger heads are becoming more and more common because mother+child no longer just die when they do occur. We really are removing selection pressures!

That's a nice way to put it. My personal opinion is that Darwinian processes are certainly optimization algorithms, they are just not necessarily optimizing for the same thing as what we might think. As an example, survival is a long-term game. I'm sure there were more aggressive adaptation strategies that went for the local minima and succeeded in the short term, only to be surpassed by the more "patient" algorithms.

There's a huge difference between "exploit in the now" and "exploit, but still be viable in a billion+ years".

A great example of this is a virus which is optimized to spread so quickly and aggressively that it extincts itself by wiping out its available hosts.

The Greedy algorithm at work.

Why didn't Boeing or Lockheed Martin make reusable rockets?

Von Braun originally proposed reusable boosters, although he had in mind a parachute system with a water splashdown. A recovery system for the Saturn V was considered, but it would have added time to the schedule, and the "man/moon/decade" goal would have been at risk.

Alan Kay should remember that evolution includes random mutations that get you out of local extrema, and "interesting" recombinations. The rate of these is maybe low, but there are examples where large organizations renew themselves this way. But I agree with the conclusion that this is slow and unreliable.

Alan Kay majored in molecular biology and mathematics ... so he probably does understand just how evolution works. (Hint: the Internet is a good source of bios to look at before making assumptions). We put in a fair amount of work many years ago on personal computing and the Internet so that people can be a few typed characters and clicks away from much of the knowledge of the human race ... what does it take to get people to make use of this?

There's a paper out there with the title "Cognition is not computation; evolution is not optimization". I haven't read it!

I'm not sure you are accepting the basic principle, which is that evolution is not in any way optimization (not that the evolutionary process is not "optimized").

See something like https://en.wikipedia.org/wiki/Fisherian_runaway

Also Giuseppe Longo's work on randomness as a cause of organizational complexity in evolution: http://montevil.theobio.org/en/system/files/articlepdf/Longo...

The important bit is evolution is not optimizing for things humans understand. If you say evolution is optimizing for more copies of your DNA fragments your closer to the truth than saying 'fitness' in larger contexts. Don't forget there is more biomass in single celled organisms than single celled organisms. In terms of 'fitness' that does not seem like progress.

Optimization implies "teleonomy", the idea that there's a goal toward which evolution is working, however obscure to us. The interesting question IMHO is whether such a goal exists, somehow expressed or implied by the laws of physics. Jeremy England's work on thermodynamic reasons for the emergence of configurations/mechanisms/organisms that are good at dissipating energy is an example of recent research that asks why we have these complex organisms at all, and tries to answer that question with pure physics.

Not really. A fire's heat creates conditions under which fire more easily spreads by drying out the surrounding area. That's does not suggest needs / wants / goals etc it simply a statement of what happens in very specific circumstances. Further, while evolution might seem to be dissipating energy, oxygen + coal is a much larger reserve of energy than you get in similar environment without life.

And the rate of random mutation varies, influenced by evolution. Eukaryotes even have two sets of DNA, mitochondrial and regular, with very different mutation rates. The complexity of biology, I think, is greatly underestimated by most.

If you are more on the side of accepting punctuated equilibrium, then this isn't true. Organisms will evolve to the local optimum and then stay there. By definition, since most mutations will result in lower fitness.

It's only when the environment changes (rise of mammals post dinosaur-extinction) or the organisms themselves change environment (Darwin's finches) that you get the rapid rates of evolution to find the new optimumm.

Some obvious analogies of these two situations in tech are the rise of the Internet (Microsoft did change, but struggled), and the rise of the smartphone (Apple came from nowhere to a position of dominance).

Why didn't we have electric cars before tesla?

Mostly because batteries sucked. Small electronics drove most of the research to improve them.

I guess Tesla vehicles are market leading in several ways, but they aren't a generation ahead of what anyone else can do or anything like that.

We should eliminate the things other agencies can do from discussions like this one. It's not about what other companies can do, it's about what they are doing. Sure, any major car manufacturer could produce a strong competitor to the Tesla, but they aren't.

I dunno, if you've got $40,000 and a tight schedule you probably end up with a Bolt.

But sure, no one is out there doing anything other than Tesla.

And I think I am giving credit where credit is due. Battery research made a lot of progress, Tesla used the resulting batteries to make nice electric vehicles. I mean, they have a battery partner and all that jazz.

Agreed that Tesla likely couldn't exist without battery technology that's developed only in the last several years, however, a Tesla is a lot more than a battery. No company has stepped up to say, "let's build a consumer electric sports car" or "consumer electric SUV" or "consumer electric luxury sedan", and that's probably down to stale corporate culture more than any single other reason.

> It seems strange to think that companies would leave money on the table, but in older industries I think this is exactly what happens.

This is probably true, but it's also deeply heretical for believers in market efficiency.

or evolution...

An interesting aspect of carrying cars rather than trains is that it makes an incomplete network far more useful.

A public transportation network's usefulness is roughly quadratic in proportion to its size, because it needs to cover both your origin and your destination. A small subway system is nearly useless, because even people who live or work near it probably don't live and work near it. You can mitigate this to an extent with busses, taxis, letting people park at stations, etc., but there's still a lot of friction.

By carrying cars, these tunnels will act as an extension of the road network, which almost certainly covers your origin and destination already. The tunnel part doesn't need to serve the ends, it just needs to exist somewhere in the middle to be useful.

If you build one subway line, it's pretty much "great, let's finish the system so we can have something useful." If you build one Boring Tunnel, it would be immediately useful for anyone whose car trips are vaguely in that direction.

I'm really skeptical it'll all work out, but I don't think it should be thought of as a lame subway.

I was thinking the other day how sweet it would be if it was easy to take your bike on the subway.

The DC Metro lets you do this, and I've taken advantage a couple of times. It is pretty nice. It vastly increases the effective reach of the network.

Unfortunately, they don't allow it during rush hour due to space constraints, so it's not nearly as useful as it could be.

The MBTA allows this during non-rush hour times, and most buses have fold-down bike carriers in front.

Indeed. This was implemented here ~15 years ago. The initial fears "Just ride the damn bikes! Trains full of cyclists! Cats and dogs living together!!!" did not materialize, and it's a major improvement on a bike's radius.

If there was ALSO public transport that used the tunnels, that would be awesome. I'd be all over a Boring Bus/Boring Capsule...

> 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 booths/machines, electrical work to power all that fun stuff, connectors to existing depots so that maintenance workers can come and service the cars and the engines.

His idea is closer to Madrid, which has dug tunnels to relieve the city streets of the traffic. The tunnels themselves are very unassuming and look like onramps and underground parking garage entrances.

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 <2min intervals at peak.

Everything about Musk's idea seems absolutely terrible. If America had better trains and subways, it could move massive amounts of people. Train automation is a solved problem, and currently implemented in cities around the world. There is absolutely no possible way in any reality where individual car/pod transport could even approach the capacity of real mass transit:


Americans need to get over our wasteful individualism, our "alone time" in cars and realize you can read a book, watch a movie or do something not involving driving on real public transport. Buses need to stop being just a means of transport for the poor.

> If America had better trains and subways, it could move massive amounts of people. Train automation is a solved problem, and currently implemented in cities around the world.

In most European cities, if you get off at train station, you're in the midst of (or very close to) the city center, office locations, touristy walking sites and plenty of choices for retail or food.

In the US once you get off at the train station, well, you're at the train station, and now need a car to go anywhere you actually need to go. NYC and SF are likely to be the only exception - train stations as close as LA or San Jose are fairly sparse and have limited connections.

You can run the fastest most frequent train you can handle, and California in fact is building one between Borden and Corcoran, but the "step 2" in US cities generally involves getting a car.

Yes, and station location is an aspect in which US trains could be made better, by building new ones.

There is no right place for a train station in a sprawling city. An effective train station needs a certain amount of stuff within walking distance, which is only possible if the city is built that way.

They didn't become sprawling cities on their own. If you plant down rail, the city reshapes over time. The areas right next to stations becomes high value retail space. Their sales immediately jump up. Rails literally change the commerce and economy around their points.

The best place to build a rain station in a sprawling city is where you can build a small city centre around it. (Hint: it's not asking a highway)

For many cities, not just NYC and SF, but yes, it is true only for major cities.

EDIT: embellishment due to baq, this tends to be true of cities which developed before the car revolution of the 50's and 60's. For example, my city has a pretty poor average walkability score, but for where I live in the city core, it is very walkable since it is the older part of the city.

s/major/old/ which were growing when rail first appeared in them. otherwise it's not reasonable to plan the city to have rail sometime in the future.

> In the US once you get off at the train station, well, you're at the train station, and now need a car to go anywhere you actually need to go.

This lesson seems to have been lost for some reason but infrastructure is to be built first, destinations second. Much of the New York City Subway system, like in the Bronx, was built through farmland. Once the infrastructure was built, destinations (dense residential) was built. It has to work that way. It's not practical to expect there to be any destinations available when the subway opens- people need a few decades to rearrange themselves.

> NYC and SF are likely to be the only exception

Portland should probably join that list.

And the Boston metro area.

And Toronto and Montreal.

If you own a car company, you want cars to be a big part of the transportation system.

> 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.

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.

This system applies to moving people just as much as moving cars. But for political reasons it makes sense to emphasize the extent to which this is about car owners.

also what about safety? If there is an accident then you will have a huge pile of cars/sleds crashing into each other; How do you get injured out of a narrow tunnel? What about fires? What about ventilation (in case of fire) ? These are all problems of tunnels, now the narrow tunnel makes these problems more difficult to deal with.

No, you'll have at most one. The cars will be networked and by having a vertical rail will be able to brake very quickly.

there's nothing stopping a specially sized bus from using the system or cyclists (if they adapt it right.)

The video on their homepage shows a cyclist on a "minibus" pod at 0:45. https://i.imgur.com/2QkC5YK.png

nice catch

Absolutely. And the biggest problem is what to do with all those cars in the city. It's an enormous waste of space to park all those cars, besides the enormous hazards of the moving cars, not being to be able to walk. It destroyed cities.

That's why public mass transport was created and was so successful in the big cities. US big automotive destroyed most of this working infrastructure in the last century (E.g. Los Angeles, Houston, ...) but it's still cheaper to build mass transport than to support individual transport. Just ask a New Yorker or a foreigner.

Tunnels are a hazard for individual traffic. That's why pods do help. But trains are still preferred.

It's a good alternative idea to build long range tunnels. He is right. But the focus needs to be mass transport, not individual. It's a matter of costs.

If there's a tunneled transport infrastructure with cars moving around on sleds, you just need a few mile length tunnels off in nowhere and you've made a robot parking garage.

You could rent your car back to the system to use as a lounge for people who want to travel but didn't bring a car to get on the network. Saves you parking costs, maybe an operator could work out paying you for that.

Yes, you could do that in midsized cities with underdeveloped public transport. Because there you would need a car, esp. when buying bigger stuff.

But for big cities trains are much better and cheaper.

> And the biggest problem is what to do with all those cars in the city.

Tunnels are great parking structures. Cars on sleds provide a great interface to said parking structure. Heck, NYC has automated parking structures with car elevators and sleds. The only imagination required is not having to dig a big hole down to the depth of the lowest level of the garage first.

One problem is that trains only move an insane amount of people that are all going the same way.

Another problem is that all those people have to walk to and from the end station.

A "packet switched" system of sending individual cars at high speed solves both those problems, and going just by my gut feel, should have a quite high throughput too.

Here in Melbourne, I used to have a bit of a "gut feel" that it might not be efficient to give over two entire lanes of our roads to our light rail vehicles. Having two lanes sit empty for so long between trams seemed so wasteful. And for what, a single vehicle to come through every minute or two?

Then I sat at an intersection one day and counted how many individuals were being moved through two lanes of regular car traffic vs how many came through on the light rail.

I was shocked by how inefficient regular traffic is.

So now MY gut feel is that without any technological breakthrough, this sort of system would already be starting with an order of magnitude disadvantage: which is to say, shockingly inefficient compared to allready available technology and solutions...

>One problem is that trains only move an insane amount of people that are all going the same way. Another problem is that all those people have to walk to and from the end station. A "packet switched" system of sending individual cars at high speed solves both those problems, and going just by my gut feel, should have a quite high throughput too.

People are walking from the station to these giant office towers in central London. The walk from the Tube station to the office must only take 5-10 minutes, total. My gut feeling says the throughput won't be high specifically because you'll have 800 or so people trying to get out at the same place at roughly the same time.

Sure, this system works great in the center of one of the biggest cities in the world. That's not in dispute.

Where mass transit struggles is in getting people from one arbitrary spot to another at an arbitrary time.

The throughput will be tiny because cars take up so much space. http://humantransit.org/2012/09/the-photo-that-explains-almo...

And cars more inefficiently in groups. When at lights, the first car pulls away, then the second, etc etc...

There is a delay between each car which after 20 cars really adds up.

This doesn't apply to the centrally controlled car delivery system Musk is planning.

> This doesn't apply to the centrally controlled car delivery system Musk is planning.

How would that work? Now it's true that there won't be any delays caused by drivers not paying attention, but unless the cars will go 125 mph with only a couple meters of space between them (eep!) the cars will require a non-zero delay "off the line" to allow them to spread out as they gain speed.

I don't think they need any space between them as long as they're on the same path. They're parked on centrally controlled carriages.

How fast they can fork and merge is more interesting, and I dare not have an opinion about that.

Centrally controlled trains are still required to be spaced out by their stopping distance. The only way this or hyperloop will do better than trains is through regulatory arbitrage.

Quite the opposite: the requirement to be spaced out by their stopping distance is regulatory arbitrage; if the design was "it might, in corner cases, crash and injure people, but who cares, they knew the risk", you could run trains far closer together (which happens all the time in manually controlled streetcars: tailgate the other tram and pray the guy in front won't slam the brakes).

Regulatory arbitrage is when you profit from a difference in regulations. If someone could figure out how to run a train but have it regulated as a car (with car-like safety properties) they would be able to run an extremely high-capacity service; I suspect this is Musk's gameplan.

They all change speed at the same time, so there is no need to space them out.

Why are you assuming that there won't be minivans on the sleds? Or a larger format sled that can accommodate a bus-sized transport or a mid-size truck?

I think in the original video, they showed a pod with a group of commuters.

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 vehicles is slightly more viable for a private sector company. Telsa can continue to promote their car sales without that having a negative effect on the Boring Company.

This idea that a company can replace our entire existing infrastructure with a train/bus system is just purely impractical. There is the solution that seems the most obvious (current public transit), and then there is the one that is actually viable from a business perspective.

> 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't have - it's what's practical. Driving in New York isn't practical, so people take the tube - regular services, high capacity, etc. There's no way a tunnel system with individual cars, which will have a much lower capacity than a regular road, will be able to compete, neither on cost nor capacity.

Of course, if you're rich then it doesn't matter. I'm sure it'll work in SF, where there should be plenty of people that can afford it.

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

The best answer I have: the more people are individualistic, the more difficult it is for them to coordinate. Big changes like fundamental infrastructure require collective buy-in, and when you have lots of self-interested individuals who stand to gain by introducing friction into the process, costs skyrocket.

The alternative ends of the spectrum (it's not 1D) of that is more social people (dream utopia, I don't know where it exists, if at all) and more authoritarian control (easiest way to coordinate people is to have someone unilaterally decide for them).

> The best answer I have

That's an excellent answer and I think you are right. Car culture is a big deal in the US and I think the perceived independence it represents is part of the reason why.

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


* 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

  - Eliminate small coins
  - Move to metric in a practical sense rather than just official

> * make checks obsolete

Uh? What? Please explain - are you expecting everything to go fine the first time, because in the history of the world, that almost never happens.


comment of the year imo


I think LA is an even better example of where it will work. There are no trains, and the bus system is very poor.

The tunnels obviously don't make sense in places that have well established train systems, but a lot of places don't have that. Often in America, the only 'practical' way to get around is using a personal vehicle.

Your information is out of date - over the last 20 or so years, LA has built itself a train network:


  The tunnels themselves are very unassuming 
I'd wager that there is a lot of hidden infrastructure in a tunnel, which carries cars compared to train tunnels.

Ventilation, as a very critical entity, comes to mind. Also safety features are extremely critical. I live in a country with lots of tunnels and essentially every longer auto tunnel has additional tubes that are under pressure, for example. That's required if you suddenly have a burning vehicle in the middle of a narrow tube.

While car tunnels don't need to be sexy from an optical perspective there's a ton of necessary infrastructure and safety features, which aren't immediately obvious.

Maybe this changes when we all go electric, but I really don't see that happening anytime soon.

Not just that. You need telematics (you don't want cars stuck in the tunnel - if a fire breaks out, it's a death trap), you need emergency exit/access tunnels, you need ventilation tunnels, and you need all of that to run in HA mode. "Just a hole in the ground" is a very simplistic view; but perhaps this is a thought-provoking way to put it, EM is known for some radical solutions.

The Boring Company isn't just looking to build tunnels either- there's going to be a bunch of interesting infrastructure to get cars onto those electric sleds and operating them, and that'll need maintenance and access and etc too.

For what its worth, it hints that those sleds will also become public transit platforms as well - "if one adds a vacuum shell, it is now a Hyperloop pod" - but Musk will want to call it something cool like an Urban Hyperloop instead of just a subway.

>For what its worth, it hints that those sleds will also become public transit platforms as well

So this is something I've been trying to address all thread, so excuse me picking your comment.

You can only create a public transit platform by having _dedicated_ infrastructure. We know this because cities like London and Paris (and not-so-big Vancouver) all have mostly-to-fully automated trains with 90-second headways between each train at rush hour. This basically means that if once a train pulls out of the station, the next one pulls in mere seconds later. These trains are usually packed to the gills. Even one single-occupancy vehicle would decrease the overall efficiency of that system.

Heck, you can create a tunnel in each which sled contains one bus and it'd still be less efficient than the London Tube because the whole thing will take up more space, physically (these trains squeeze in every last passenger). This is what Seattle tried to do with the downtown bus tunnel and they're evicting all the buses there in favor of light rail.

I think it will always make sense for subway trains in dense city cores, but I think the discussion about dedicated rapid transit is hampered in more suburban areas because of the whole notion that we have to fit in cars into rapid transit corridors, or else it's not worth it. But this ends up making buses less reliable and gives them their crappy reputation (see: https://en.wikipedia.org/wiki/Bus_bunching).

Grade-separation is absolutely necessary for good rapid transit.

You are making too many assumptions about the system. For example, their goal seems to be multiple stacked tunnels vs a single one for metro, plus trains don't go 125mph.

BART hits 80 and is slow. 150 mph is very attainable.

With a 35mph average according to Wikipedia. Which urban metro system achieves those kind of speeds?

Well, my city has dug tunnels to redirect ground traffic. Result: traffic on top abates for a few months, people notice, more of them start driving, now we have tunnels and the same level of surface traffic as before. Yay.

With the capacity in mind, this project will end up having much lower throughput than a regular road, even when taking congestion in mind - unless they build dozens of parallel tubes, in which case the costs will become very, very large. I also don't see it becoming a long-distance alternative, again because tunneling is a slow and long process.

It would be interesting I guess if they combined it with the Hyperloop concept, board the tube system in the city, transition to a (cheaper?) above-ground vacuum tunnel system at a transit station.

But it's all very science-fiction and, if anything, it's not going to be cheap. Like, at all.

At least it's a commercial project, not something a government has to pay for.

It's not science fiction, it's just drilling holes in the ground vs waiting for flying cars.

It may be expensive - but you only have to build each tunnel once.

There's a startup that got some hype recently for flying an electric airplane between London and Paris - when as someone commented on the HN story [0] you can just take the Eurostar through the tunnel - which is electric and takes just as long and doesn't cost any more.

[0]: https://news.ycombinator.com/item?id=13930880

I'd guess 1 lane at 200km/h without stopping is ~7-10 lanes rush hour traffic.

In traffic, you have to look at both throughput and carrying capacity. Traffic jams usually result when the carrying capacity gets strained, not throughput. (The throughput of stop-and-go traffic is lower than the throughput of 70 mph traffic, but the road can carry more cars in total, so that equilibrium dominates when the load coming from surface streets exceeds some threshold.)

Without stopping and without merging. The proposal acts as if entering/exiting a tunnel at any depth is zero-cost and zero-size.

I think you're missing the point. Of course trains are better. So why don't we have more trains?

Because people have opinions on trains. So instead of building train tunnels you debate it for 20 years in town halls and NIMBY protests and nothing changes.

This is clearly a hack around that issue. The article mentions a Hyperloop several times, that's the ultimate goal here.

As interest in car ownership drops as the Millennials age and take the older generations' place, that problem may fix itself.

What do you mean by interest in car ownership?

While this article[0] demonstrates that numbers have improved slightly for actual car ownership as millenials age, it still contains other tidbits and statistics (like the having driver's license by 18 stat at 60% vs. 80% in 1980) that reflect views on car ownership amongst millenials today.

Anecdote, I don't have a lot of mileage (pun unintended), but every girl I've ever dated did not have license, and neither do I, and I am 27. I live alone and bike and bus ride for the most part.

[0] http://www.latimes.com/business/autos/la-fi-hy-millennials-c...

Don't make the mistake of making macro predictions based on a niche segment. I think generally people aren't "interested" in car ownership; they are interested in fulfilling their transportation needs as best as possible. Car ownership just happens to fulfill that the best right now.

There is the possibility of increased urbanization and improvements to self-driving car technology will make it economically feasible for car ownership to be unnecessary for most, but I highly doubt that happens within the millennial generation. Probably the next one.

I agree. I couldn't be less interested in owning a car. But in the US unless you live in certain few cities, you can't really do without one. And those cities are very expensive.

One of the reasons that subways are built only in very large cities is that you need a very high population density to make it worthwhile because of the cost of digging the tunnels.

But what if the cost were a tenth as much? I posit that for a city of 500,000 - 1,000,000 it might become practical to have subways and that radically changes the transit equation.

So I am very bullish on Musk bringing down the cost of tunneling. It all depends on how low he's able to reduce the cost.

I've got confidence in them too. I think internet commenters are far too quick to overlook the fact that Musk is not going to push forward a venture like this without loads of research from a team of really smart people. It's not like it's just the one Elon with a fantasy about tunnels. It'd start with a bunch of talented people brainstorming and then, early in the process, they'd surely be speaking with really knowledgeable people who know the industry and pitfalls.

If smart and motivated teams can't do something, can anyone?

With something like soil, maybe they figure the technology will be useful even if it only services projects with easy terrain and environments and avoids areas with swamps.

> Musk is not going to push forward a venture like this without loads of research from a team of really smart people. It's not like it's just the one Elon with a fantasy about tunnels. It'd start with a bunch of talented people brainstorming and then, early in the process, they'd surely be speaking with really knowledgeable people who know the industry and pitfalls.

Actually, the story is that Musk made it up on a whim while stuck in L.A. traffic, founded the company the same day and bought a used drilling rig which started digging in the Tesla parking lot.

OK, it'd start with a user frustrated by a problem, then go to brainstorming with colleagues/employees/peers/friends and then go to industry experts and hires with direct experience. ;)

Really the main difference is that someone without money and follow through would've just sat in traffic and complained.

Follow through = billions in the bank and oodles of connections

You're implying that Musk's "follow through" is a result of his money and connections, when the reverse is true.

Yes, of course, now that he has money, connections, and a powerful reputation, that makes it easier for him to do things. But he created the money, connections, and power by being able to do things even when he had none of them.

Obviously that eases the process but some people follow through and some don't. Some have big dreams and some just invest for themselves only. I can think of loads of rich people who aren't out there starting companies to push forward space exploration, car technology, tunnelling machines, etc. He has pretty serious runs on the board now.

Same as the Hyperloop story. Just that the Hyperloop story wasn't true, it was really conceived by Et3.

And in general - entrepreneur "origin" stories are often bullshit - useful to get go PR, that's it.

>the Hyperloop story wasn't true, it was really conceived by Et3

You might want to look at them closer. Hyperloop and ET3 are very different from a technical perspective, even though they're superficially similar.

ET3 tubes need 1/1,000,000th of an atmosphere to mitigate the sonic boom, and that makes the pumping requirements exceedingly hard (requiring multi-stage pumping with turbo- and cryo-pumps). That also means ET3 has a higher top speed, assuming you can secure the right-of-way to satisfy the minimum curve radius.

Hyperloop tubes use 1/1,000th of an atmosphere, chosen because it's the lowest pressure achievable with purely mechanical pumping. They then route air around the pod, allowing them to approach the speed of sound despite the fact that air has to speed up as it squeezes around the pod (aka the https://en.wikipedia.org/wiki/Kantrowitz_Limit).

So ET3's pumps see basically the same differential pressure, but 1,000x more volume needs to be pumped per m^3 of air that leaks in. This means the Hyperloop requires less pumping power, fewer pump units, uses only cheap mechanical pumps, and can tolerate more air leakage than ET3. This is a big win, since the tube is the expensive part.

Yes, smart people are magic. Doesn't matter how much sense the idea itself makes, one only needs to ship it off to those 'motivated talented people', they will figure everything out.

Indeed they are. As any experience with anything remotely more complicated than building a cube out of Lego bricks should tell you. For any practical problem there are many ways to address it that may not seem obvious in the first five seconds of looking at it.

machines heavier than air will never fly, obviously.

let's judge the outcome - or lack of it - when they fold or succeed.

> I posit that for a city of 500,000 - 1,000,000 it might become practical to have subways and that radically changes the transit equation.

Cities of 500000 inhabitants which have a subway exist. See


It's worth mentioning that the smallest city with a rapid transit system (2 metro lines, 28 stations) has a population of only 135,629.


Lausanne recently took the smallest-city-with-a-subway title from Rennes, France (214k).

My family is from Lausanne and I spent a few months studying in Rennes–the size and density plus the metro system makes these cities really pleasingly 'human scaled' in my view. Walking-first center city areas with lots of restaurants/shops, easily accessed from less dense areas by metro+good bus systems+intercity train, but small enough overall to not feel sprawling.

Many European cities of such sizes already do have subways.

He's trying to hit a price point. We're not completely allergic to the $20M freeway bridge that's about 100ft long, and comes with heavy upkeep costs over the long term. 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.

> 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 regular track and station rebuilds, so the tunneling figure is really closer to $15 billion.

That's about $570 million per mile, but the Crossrail tunnels are just shy of 50% bigger in diameter than what Musk wants to build (20.5' vs 14'). And as the FAQ says, "reducing the diameter in half reduces tunneling costs by 3-4 times".

LA's tunnel might be costing $1B/mile, but how much of that cost is actual construction versus bureaucracy and mismanagement?

[1]: http://www.crossrail.co.uk/construction/

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 the Regional Connector project, which will be 1.9 miles of light rail and has a budget of $1.8B. But that's the entire project budget. Tunneling costs are only part of it; it's hard to find a finely grained budget, but total construction (including four new underground stations) is budgeted at $1.2B here [1], which is still "just" $600M/mile.

[1]: https://mtadash.mlmprojectservices.com/projects/5773#/cost

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.

Well, that's some adverse conditions - a silt riverbed behaves quite like water, so you're actually building a submerged part of the city. Look at London's early tunnels and their cost overruns (and the maintenance due to leaks).

No, crossrail tunnels are WAY less expensive than that: http://www.crossrail.co.uk/news/articles/crossrail-awards-ma... It's about 145M$ per mile that is well in the range of 10 times less the outrageous cost that they pay in US for a single mile.

> 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.

A few reasons off the top of my head:

- flexibility; car infrastructure is much more flexible than train infrastructure

- incremental construction - cars already exist, you're only solving the problem of moving them around (building train infrastructure means building more trains with additional train-supporting infrastructure and more railroads outside of tunnels)

- meshes well with electrification of car transportation

- allows to reduce fossil fuel polution with minimum impact on people's habits - instead of asking someone to start using trains, you just ask them to drive into a tunnel, and for the duration of tunnel transit, the pollution (and fuel costs) magically disappear

- related, it's easier do incremental changes than all-out revolutions

- R&D in efficient boring could be of vital importance to future Mars colony

- last but not least, electric PRT system (aka. "packed-switched" public transport) could be, and probably will, incrementally implemented with self-driving electric cars; this again meshes nicely with that future (benefits of PRT over other forms of public transit are a longer topic)

> you just ask them to drive into a tunnel

Presumably whether this system is privately or publicly operated, there would be a major toll associated with its use. So the ask isn't just "drive into a tunnel", it's "drive into a tunnel and pay $$$", compared with a new subway line integrated with the existing mass transit system (trains and buses) and under the same fare.

I suppose you could let people buy monthly tickets the same way they do for public transit, and handle the rest the same way automated ticketing of speeding is handled.

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 significantly less hassle as you don't need to figure out where to put railway cars when they get the end of the track. Finally it's costs would scale fairly linearly with distance, making short belts totally doable in a way that short railway systems are not.

The natural throughput of the system will be high. Like a new car on the belt every x seconds, where x is not a big number, seems totally plausible.

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

How about bus pods directly after bus pods? It'd be comparable or even higher (20 passengers/pod).

Congratulations, you just reinvented the train.

Yes, but it's a train that also carries cars. And quite possibly freight.

Those aren't new either, but not common for urban transportation.

Generously assuming that it averages 150mph, and very generously assuming 1.5 people per car and estimating from the video a gap between sleds of 40m gives a capacity of around 9,000 pax/hr per line. The Tube in London has trains with around 900 pax capacity, and they run at around 90 second intervals at peak time, giving 40 trains per hour and 36,000 pax/hr.

One point people seem to be ignoring is that Elon mentions on multiple occasions that he plans to build in 3D, i.e. not just one layer of tunnel in one direction but multiple tunnels at multiple depths in multiple directions i.e. to get your 36k pax/hr will require 4 layers.

Well, of course those tube numbers are per line, per direction too.

It's already been mentioned that putting cars in the tunnels increases the usefulness of the tunnels quickly without requiring a large network of tunnels right off the bat. I think it's always possible to convert the tunnels to trains at a later date with a much lower cost than the initial investment. I think having the tunnels be designed for cars makes a lot of sense for Elon in particular because he can design the tunnels as an ideal environment for the first generation of self driving cars. This would give him a good start getting self driving cars on the road.

> If what he thinks he is on to is viable with cars in those tunnels, it's even more viable with trains

In Europe, that would be true, but I think in Southern California he can charge exorbitantly per car and people will pay it.

In order to be useful trains need to form large network. Few mile subway route is not so interesting.

A tunnel for cars is different. Even a single and relatively short tunnel is useful and people would probably pay something for access. This means you would start making money on the investment quite quickly.

I agree that trains are the right thing to do, but that is much larger project and likely too big to be an option for private company.

> but starts by quoting a very high benchmark of $1 billion per mile which is quite easy to beat

Now I know why big companies do those reading comprehension tests...

He didn't say that was a benchmark at all. He explicitly said that was one of the highest costs for tunnels.

> with some projects costing as much as $1 billion per mile

the smaller diameter is because he's building for cars and not roads, and as for trains I think he need the early adopters aka, the rich to invest. mass transit is for the poor and doesn't attract investors. but in the long run it's probably better. but if you look at the mockup video there's an mpv that enters the tunnels, not just teslas.

I think it's move polivalent to transport vehicles (personal or mpv) that way the last 1-5 miles can be resumed by the vehicle and they don't have to stop everywhere (which is the main crutch of trains), you want to cover as much area and not have "why don't you stop near my house" syndrome.

there's also nothing stopping bicycle riders from using the system provided there are seats to strap into and goggles to wear.

"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?

It's mostly due to how much people prefer personal transportation over public transit.

There are obvious benefits of being able to come and go as an individual instead of relying on public transit.

Hygiene, safety, and storage all pop to my mind.

I kinda wonder if the tunnel-borers are meant for Mars.

Not to mention that (like other Musk projects) scalability is a huge issue.

What's the throughput of cars on electric sleds through tunnels?


Maybe the explanation for glossing over some of the obvious hindrances (that you and several other commenters wisely point out) is that these projects are not conceived out of an organic need or to problem-solve issues - even though they are projected as such...but, these are projects that are born out of some (unpublished) masterplan/roadmap for learning to establish a colony on Mars.

Just learning how to build tunnels is interesting from that respect.

The reason that isn't stated is because Musk likes to create projects around a "purpose" and business plan for them to succeed (even if they are retro-fitted - that is, he decided first that it would be important to tunnel, and then arrived at the "why tunnels on earth").

edit: not a new thought. some other commenters already pointed this out. I read those after posting this.

Yeah; come to think of it, any reasonable project of bootstrapping a viable Mars colony with present-era tech would have to involve tunnelling, as it offers many benefits at the cost of only shipping construction equipment and delivering electricity. I could totally believe Elon has Mars in mind with this project.

> Issues glossed over: Soil variability. … The back end.

Good points. And beyond the technical aspects, there's a lot that the FAQ doesn't say about the service:

- How do you tell your sled where to go? Does it always go to the same place? If so, do you merge lanes? If you merge lanes, wouldn't there be jams there? If instead you build many parallel tunnels, don't you remove the gains you had from building smaller tunnels, by having many more tunnels?

- How is it meant to compete on price or human bandwidth with subways? Surely at 200 km/h you need to maintain space between sleds in case one fails. Plus, the sleds are not large, which limits human bandwidth. Finally, if you have lots of tunnels (at least one for each origin/destination, instead of subways with many stops), you will need to maintain and repair that infrastructure, which will require service tunnels and backup tunnels, which adds to the cost.

Another thought: they don't mention how they'll design the tunnel network yet. My guess is that it will be backboned by double circular tracks (one for clockwise driving, the other for anticlockwise), from which you have regular exit/entrance ramps at each stop. The circularity would avoid having a terminus where everyone slows down.

Still, any design would have a maximum capacity corresponding to how fast vehicles can exit in the worst case, if they all suddenly decided to leave at the exact same stop.

>How do you tell it where to go?

the giant ipad on the dashboard of your tesla, or your phone otherwise.

>If you merge lanes, wouldn't there be jams there? If instead you build many parallel tunnels [etc]

because if the increased speed, one lane is the equivalent of about 2.5 highway lanes in terms of throughput per hour. Regarding safety distance, I think you can actually safely achieve smaller spacing with a roller-coaster style mechanism than with tires on asphalt. I would say that as well is a 2x throughput multiplier. So parallelization seems largely unnecessary.

>How is it meant to compete on price or human bandwidth with subways?

ok so take an 8 car subway train with 40 people per car on a 10 minute interval. 8 * 40 * 6 = 1920 people per hour travel from A to B.

then take sleds each containing a car with 2 people, paced 300ft apart traveling at 125mph. that is 2 people * (125mph / 0.0568182mi) = 4400 people per hour

> take sleds each containing a car with 2 people, paced 300ft apart traveling at 125mph. that is 2 people (125mph / 0.0568182mi) = 4400 people per hour*

I think 300 ft is for 75 mph. Using https://en.wikipedia.org/wiki/Braking_distance, the distance at 125 mph is 55 m/s * 55 m/s / (2 * 1 * 10 m/s2) = 150 m = 500 ft, resulting in 2 people * 125 mph / 0.09 mi = 2.8 khumans/h.

(On the demo video, their vehicles look like they are tire-on-asphalt.)

Also, subways have a typical capacity closer to 30 khumans/h in dense urban areas (https://www.thoughtco.com/passenger-capacity-of-transit-2798...).

The vehicles use a monorail, not asphalt. Both in the concept video and the actual prototype of the electric sled in a tube video.

Also, the concept video shows multi-user pods. If you pack them as full as a rush hour subway, you could probably equal or exceed a subway's throughput.

I think your assumptions are not valid. Subways usually go much more often than once per 10 minutes.

In the US?

In NYC, yes. During rush hour, the local subways come every 5 minutes at most. I think a safe estimate is about 15 trains every hour.

The express subways are spaced out a little more, closer to 8 or 10 minutes, depending on the line.

peak of the most active system is not the same thing as "usual"

here is LA for instance, about 10 minutes average during rush hour https://media.metro.net/documents/5a366ef8-2013-4d21-8e6d-e7...

Using actual numbers:

Melbourne's light rail E-class trams have a carrying capacity of 64 seated: 146 standing. They can regularly mix with pedestrians. The E class is the "big" one at about 40 seconds:


Melbournes older, 6 car trains have a crush capacity of ~1526. Seatwise they have ~500-600, with a standard target capacity of about 800 (above that the extra variance/numbers people start to complain about overcrowding).

Seen here:


Now, those old trains aren't the newest, and they're single-decker and not the biggest or double-decker like sydney's, and they're not the bestest like some of the asian fully-auto metros.

But, my point being is that by the numbers before we start getting too crowded, our quite average older 6 car trains have point in time comfortable capacity about 2-3 times more than your 8 car subway estimate. Hell, three of our light rail vehicles regularly move the numbers of your 8-car subway.

But wait...

We've not actually accounted for the trips accurately, because if a train runs the full length of its track only carrying its estimated point in time comfortable capacity, the carriages would be quite empty: the total passengers using a train aren't its point-in-time-carrying capacity, but how many get on and off between all the stops along its path. That goes for light rail too. So to find the actual number of people moved by train or light rail, you generally have to multiply the carrying capacity by some additional multiple.

On the other hand, private vehicles generally, in practice have a person per vehicle estimate UNDER 2 (barring geography, time, purpose variances), meaning your estimate is overly optimistic for the cars, and out by about an order of magnitude for the rail vehicles.

I was not being facetious when I made another comment in this thread when I said I was shocked by how inefficient private vehicles were when I actual went down to the intersection and started counting how long it took them to move say 100 people (equivalent of 1 of our trams), nor am I being facetious when I say not only that this is likely a problem with an already known solution, but a problem where The Boring Companies apparent solution is starting with a rough order-of-magnitude efficiency penalty.

I'm honestly a bit...feel like I'm taking crazy pills...that people are talking about the proposal of putting private individual vehicles on rails...in tunnels.

I totally agree with you that cars are hilariously inefficient. Let alone single occupancy cars.

The problem is that most US cities are completely unwalkable, so you need a car once you hop out of the station, or you need an incredibly large subway system.

This is being proposed for LA initially, which is one of the most sprawled, least walkable cities in the US.

I wish we had more walkable cities here.

TBMs can turn, albeit slowly. Bigger tunnels are not necessarily more efficient than parallel tunnels. Consider changing a 1 lane to a 2 lane tunnel. You can dig two adjacent tunnels, or you can use a TBM that is twice as wide, and therefore has to remove 4x as much material. Even if you can only build 2 or 3 TBMs per bigger TBM, it's a win.

The tunnels are still pretty big, and the sleds could be 10' wide and 10' vertical if the tunnel ID is 14'. That's pretty comparable to a subway or bus, and the increased distance between the sleds is made up for by the increased speed.

For someone interested in tunnel projects whose budget has gone overrun: Hallandsåsen in South Sweden. Mudy soil made for difficult digging.


"- Soil variability. Very different techniques are required for different soils. Sometimes the soil has to be "conditioned", adding something to make it solid enough it can be drilled through.[1] This is the biggest practical problem in tunneling. Too much water is the usual problem."

Too much water won't be a problem on Mars... where I think the end-game here is for Musk on why he's learning how to build tunneling machines.

Fine, dry sand is also a problem. It leads to "over-excavating"; you keep digging and removing material as more slides down. You either get a big unwanted cavern that has to be supported, or break through to the surface.

In my fantasies I've got a microtbm which digs a 4" diameter tunnel over to San Jose right under MAE-WEST so that I can pull a fiber right to the Internet :-)

For the soil variability, is that hit when the TBM gets to a bad patch, is some kind of geophys carried out beforehand, or are there probe TBMs?

I suspect having mini TBMs which go ahead of the main machine, boring small tubes would be an effective way to give feedback on what's coming up; avoiding nasty surprises / helping to prepare ahead of a change of soil type.

Soil testing by drilling small vertical test holes with well-drilling equipment is routine. This would be essential in Los Angeles, which is a mountain range covered by sedimentary basin fill. Here and there the mountain range peeks above ground, which is why you see some rock outcroppings in mostly flat LA. The mountain range is still there, underground.

It is well-mapped. LA used to have an oil industry, with oil wells all over the city. So the underground has been explored and studied by the oil industry. UCLA has been studying Los Angeles area geology since the 1920s.

Exploring horizontally has been done for a few projects that lack vertical access. Eurotunnel drilled the service tunnel first. Some mountain tunnel projects in Japan did horizontal test bores. You can't do this directly ahead of the main TBM without interfering with the main dig.

JFYT, that is a technique widely used, but normally not on tunnels that are (final diameter) TBM excavated, only or those that are excavaed through more traditional means (explosives/excavators). Basically if you want to excavate a tunnel (say) 12 m in diameter, you first bore a tunnel with a much more small TBM, typically 3.6 m in diameter.

This pre-bore provides three great advantages:

1) Ventilation of the tunnel during the enlargement is greatly simplified

2) You have a very sensible saving on explosives (if explosives are used) or however faster excavating times (because a large part of the amount of explosive is needed to "start" the demolition of the rock, i.e. pull the center "core" out)

3) From the pre-bore you can (when you encounter problematic terrain) drill radial holes for consolidation of the surrounding terrain (though cement injection or other similar techniques)

If the final diameter is TBM excavated as well, #1 advantage above is only partial, #2 is almost non-existing while of course #3 remains, BUT, you cannot make the pre-bore much smaller than the 3/3.6 m diameter as otherwise it would be only useful as a geo prospection mean, as it wouldn't be practical to use it for anything else, and there would surely be issues (for smaller diameters) with ventilation.

AND the other bad news are that - more or less and as a first approximation - a TBM has an operative tunnelling speed of roughly 400 m/month that is almost independent from the diameter (while a traditionally excavated tunnel is more around 100 m/month without pre-bore and 120/130 m/month with the pre-bore), so while it may make sense (of course a lot of factors are involved), if you have a 4 Km tunnel to make a pre-bore that will add roughly 12 month to your 50-60 months project excavation time (traditional), it won't make much sense unless for other very particular considerations to add those same 12 months to the 12 months a full face TBM would take.

What is often done on full face excavated tunnels with TBM is prospection holes (horizontal, drilled from the face of the TBM) in the 30-50 m range, to explore what lies ahead in the immediate future.

>he has lots of experience with high-torque electric motors.

From where?

Tesla, obviously.

Electric car motors are not anywhere near high torque. They're mostly designed for high speeds and go through a reduction gearbox (in addition to the reduction of the differential itself). Furthermore, the motors in Tesla cars are pedestrian in design.

Tesla pioneered mass-produced liquid-cooled electric motors. Those were rare before Tesla. Now they're much more widely used.

Tesla was forced into that technology. The original Roadster had a two-speed transmission and an air-cooled motor. The huge jolt on the transmission when it shifted during acceleration wore it out in months. So Tesla had to develop a motor with a wider power range that would fit in the original space. That forced them to liquid cooling. Previously, liquid cooling an electric motor was considered unnecessary complexity; just make it a little bigger and use air cooling. Now, it's common for electric cars and is being used for electric powered aircraft.

Liquid-cooled motors are widespread in many applications already and technically it's not something complicated. Furthermore, high torque, multi-pole motors (assuming you want to direct-drive a cutting head moving at 2-4 RPM) have little to do with with the kinds of motors used in cars.

The old strategy of hiding your outlandish claim in an assertion in the first sentence!

"To solve the problem of soul-destroying traffic, roads must go 3D"

The word "must" is a very strong one here, there are other options:

* Reduce the amount of travel that people need to do (remote work, online shopping).

* Reduce the density of cities (enabled by remote work or longer commutes with better internet access).

* Increase public transport options (higher passenger density).

* Encourage cycling.

I feel like only somebody who lives in LA would make the "must" assertion and not think about all the other options... oh wait:


If NYC didn't have a third dimension for transportation (subway and trains), no amount of busses and bikes would fix the soul-destroying traffic. The listed alternatives are all nice, but none of them allow you to move at 125+ mph. We should be able to get to our destination faster, not just with a bit less soul-destruction. Remote work is of course not for every or even most professions, and I don't see why it would reduce the density of cities. Cities are still highly desired to live in outside of work

> If NYC didn't have a third dimension for transportation (subway and trains), no amount of busses and bikes would fix the soul-destroying traffic.

Yes they would. If you took the existing surface street network and made it 100% buses and/or ground-level trains you could accomodate current subway and road capacity with room to spare, even before you reclaimed all the space currently used for car parking. Private cars are an astonishingly inefficient use of space, and taxis are barely any better.

> The listed alternatives are all nice, but none of them allow you to move at 125+ mph.

We don't need to though. There's no conceivable need for a city to accommodate more people than could live within a 30-minute commute at current speeds if we were willing to build at the high densities that are actually possible.

"Private cars are an astonishingly inefficient use of space, and taxis are barely any better."

... and buses are even worse.

NYC works because of trains and as a proponent of train travel and public transportation (except buses) I believe they have indeed solved many problems with their diverse rail network.

Buses are a canard - they are the minimum viable public transport option that were pried out of suburban taxpayer hands and presented to poor urban (usually black) riders by planners who didn't care about public transportation at all.

This ruse has gone on so long that in 2017, well meaning (and brainwashed) proponents of public transportation see buses as one of the core components of a transport network. Wake up. This is false. You need subways and trains.

Well-functioning transit in cities that prioritize it use very few buses and they use them for weird stopgap or edge cases (or emergencies). BRT is a farce[1]. You should be demanding real, not fake, investment in transit networks. You should be demanding trains.

[1] To be fair, I have seen two very functional BRT models - both in very specific (and wealthy) environments: VelociRFTA in Aspen and Hop/Skip in Boulder. In both cases, however, a well-designed rail corridor would be even better.

> ... and buses are even worse.

London buses have a capacity of 80 to 130 people and are often full. How can that be worse than 60 to 110 cars for each bus? Even at half the capacity (single deck) you use the space way more efficiently than cars.

Now if you live in a city where the planning was botched, the transit routes made inefficient, and poorly targeted at ghetto areas that's a different problem. In fact you'd probably have the same problem if the same routes were done by trains.

Buses are just a way to transport a lot more people than cars and I can't see how that's a problem...

I agree that buses a terrible solution, but are definitely better than no public transit at all. Sadly, Seattle is almost entirely dependent on buses for public transit, although things are getting slightly better here with recent investments in light rail. Of course, the costs are astronomical and the most important parts of the project won't be complete for decades, so it's cold comfort for anyone currently stuck with a 7 mile, 1 hour commute by bus (or worse).

What's baffling to me is that, in addition to "real" light rail, Seattle is also building out a network of street-level trains. These trains barely carry more passengers than an articulated bus, are subject to the same traffic issues as the buses since they don't have a dedicated right of way, cost way more than adding bus lines, and their tracks create significant hazards for cyclists. I could be wrong, but it seems like this is an example of "buses = bad; trains = good" thinking gone awry.

Tokyo is a much bigger city. They solved the problem by building elevated toll highways. Much simpler solution than digging new holes everywhere and keeping those silly carts running.

Also by going underground. Tokyo's metro is fantastic and one of the few globally that has more than 100% farebox recover ratio.


> 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 basic service the government should strive to provide, although I'm sure some people will regard such an idea as socialist nonsense.)

I was in Tokyo recently. You can cross most of the city by subway/train for ~300 yen, or $2.66 USD at today's change rate. Compare to San Francisco, where I live. A Muni ticket is around $2.25, and a BART ticket ~$4... both with much worse service and smaller coverage.

You could argue, perhaps, that the price is expensive relative to what Japanese people earn, but from my impression it was a very effective and reasonably priced public transportation system.

I can only speak from experience for Hong Kong's MTR system. It has over 100% farebox recovery as well. Fares are distance-based [0] so it's hard to tell, but the average seems to be US$1.20 or so per person (unless you are traveling to Shenzhen) one way, which doesn't include transfers to the privately-run buses. If you believe in the Big Mac index at all this doesn't seem to be much more expensive compared to the US. (Note that it doesn't include transfers to buses.)

But the MTR actually was subsidized by the government, which let MTR Corporation develop the land above the subway to make malls and stuff, which they make even more money on. Presumably some of this profit gets reinvested into the system itself.

0: http://www.mtr.com.hk/en/customer/tickets/octopus_fares.html

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.

> because that can encourage more people to use public transit

you don't really want more people in Tokyo metro, at least not in peak hours

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.

If you are going from Kita Senju to Ginza then you would be using the Hibiya line. That trip will cost 195yen. Which is the same price for going all the way down to Roppongi where Google is. The Tokyo Metro and Toei lines tend to only have two or three prices depending on distance. This is why going two and three stations almost always costs the same.

Since employers always pay for commuting costs a regular working person spends very little on train tickets day to day. Me and my wife spend about $100 per month between us. With our companies paying a further $70 per month for each of us for our passes to work.

Living in another crowded city, Hong Kong, perhaps I can offer some perspective: We have tons of elevated tools highways and bypasses aimed at reducing traffic, the problem is all these elevated roads needs to go around a lot of tall buildings. Going underground with subway already provides us with better solution to a lot more of our traffic problem. What the boring company's proposing isn't all that different from the subway solution (we already have subway going three or four level deep), it simply allows cars to transported via subway.

That's the difference though, they're not talking about putting tons of people down there, they're talking about putting a small handful at a time (at most) by using cars. It appears much less efficient.

They talk about ALSO putting cars. There will be pods for transporting people, like in subways.

Isn't that still taking roads 3D?

What's more expensive and has long term track record success?

Pay today or pay tomorrow. I don't think it is an outlandish thought IF $100M/mile tunnels are achieved that the TCO for an elevated roadway will be higher. Elevated roadways have to be replaced eventually. Tunnels are more durable, look at the Holland Tunnel for example, 89 years old and no need for replacement in sight. And it's $48M price tag would be $3.3B today for 1.62 miles.

Elevated roads require surface space. A tunnel requires a small entry-point.

Well, given that both tunnels and elevated roads are still being built, the most expensive likely varies depending on the situation. If Musk really reduces the cost of tunneling by 10x, that calculus will shift in the direction of tunneling, obviously.

Dirt roads are extremely cheap and have been around forever. That doesn't make them the best choice in a modern society.

It's a lot easier to tunnel through sky than rock.

But rock comes with supporting structure, whereas you need to build those into "sky tunnels". This limits just how much "sky tunnels" you can make in two ways - there's only so much space on the ground you can use, and there's only so much weight it can support. That, and people will get anxious if their sky is totally obstructed by highways in the sky.

Tensile-strength-to-volume ratios for many materials is ridiculously high. Tunnel wall, ceiling, and floor quantities represent massive overengineered for that purpose

A cable tramway is one option for an aerial system. The load-bearing capacity of a 15mm steel cable is impressively high, and it can be strung along pylons.

Not that you'd want to bolt street cars to such a system, but it's an example of a possible people-mover that doesn't require persuading a multiple-kilometers-long bolus of solid granite it'd prefer being elsewhere.

Whilst I'm aware that Musk's premise here is that he can be the boringest guy ever, I'll note that the Gotthard Base Tunnel, in Switzerland, required 17 years of excavation to extend 35.5 km.


Tunnel systems can also give rise to some interesting cascade failure modes. Cab-forward deisel locomotives aren't generally considered a risk factor, until they are. Summary of an accident report, here, five souls lost to bad design of stock and tunnel, inadequate maintenance, poor judgement, and panic response:


Also, noting: the incident inquiry found for operator error of the crew. I find that conclusion difficult to justify based on the presented evidence.

Tokyo also have subways and trains absolutely everywhere, and most people use them. You only drive in Tokyo if you have a good reason to.

Also people have to accept having a highway right next to their window: https://thumb1.shutterstock.com/display_pic_with_logo/141562...

Parking is a bigger problem in tokyo if you drive, and the tolls are expensive.

The newer the subway lines in Tokyo are fun because they have to built in under the others (as referenced in the FAQ), you can tell you're on a new line when you descend down flights and flights of stairs.

OTOH JR Central is in the process of building a tunnel from Tokyo to Nagoya: https://en.wikipedia.org/wiki/Chūō_Shinkansen

Yes, for a MagLev train that achieves the fantasy of hyperloop (but is actually happening now). From my perspective, hyperloop and TBC are each 100% upside down in terms of their approach. America can only dream of 505km/hr interstate ground transport. I'm writing this from aboard the Nozomi express Shinkansen at around 300km/hr, by the way. Just left 名古屋駅.

Hah, amused to be able to read kanji after so many years (nagoya-eki :P)

I have ridden on the Nozomi and it's a fantastically smooth ride. There are indicators of the current speed on the wagon passage doors and it is incredible when it achieves 270+ km/h and everything is passing by so quickly, and yet you can drink your beverage from a cup just fine, just like in an airplane :)

I actually get more excited about riding the Shinkansen than planes these days. Planes are like buses now...

That is still going 3D but without the significant speed increase. Also it is much more beautiful and less noisy to have highways out of sight so that the city is left for people and bikes, as opposed to stacked highways towering over head.

I wouldn't consider to daily commute problem as "solved" in Tokyo ..

Next to NYC, commuting in Tokyo is effectively trouble-free. It may be crowded, but it's also predictable when the crunch times will be. Trains are on time. Cars keep moving and don't block every intersection with incessant honking.

The "problem of soul-destroying traffic" will exist for as long as driving remains the best all-round option. It's induced demand: build more roads > capacity increases > driving becomes easier > traffic increases until driving is as hard as it was.

Add a congestion charge or tolls, and a proper public transport network. The solution is not more roads, it's fewer cars.

America suffers from one more blight: too much parking. Large chunks of LA have mandatory parking no-one needs. This spreads the city out further whilst not actually providing parking where it's needed.

This worked really well in London, imo. Lots of really good transport infrastructure + city tolls make for a relatively nice driving experience.

Cities like LA will become denser over time. It might seem counterintuitive but increasing density alleviate traffic (people walk).

You can't clean a hotel or flip a burger remote.

Public transit has failed to solve the problem despite a 100-year head start.

Cycling... in LA...

I don't think the Boring Company is trying to solve the gridlock. They will, however, provide an option for those who can afford to pop down into a Teslalane [sic] for a trip to the airport. And that's fine. It's [Teslalanes] infrastructure that ultimately helps the city thrive until the time that the land use patterns rebalance. There will always be traffic - but it won't always have the same overall impact.

>Public transit has failed to solve the problem despite a 100-year head start.

I take objection to this because, aside from other cities where public transit is the norm, the interurban system in LA [0] was dismantled, partially because it was forced out by cars that increased congestion to the point that streetcars could no longer run on time, and partially because of car companies advocating that buses could replace the streetcars (they didn't).

Things don't exist in a vacuum, and LA decided to make itself a city where you could only be comfortable getting from place to place inside a car.

0: https://en.wikipedia.org/wiki/Pacific_Electric

> Public transit has failed to solve the problem despite a 100-year head start.

Public transit SOLVED the problem 100 years ago in the US. And then it was sabotaged by the big automakers.

>Public transit SOLVED the problem 100 years ago in the US. And then it was sabotaged by the big automakers.

I think American Individualism sabotaged Public Transit when it realized it could avoid the public by using automobiles.

> Public transit has failed to solve the problem despite a 100-year head start.

So the question here really is "which would improve LA more: tunnels that carry trains, or tunnels that carry carts that hold single cars?"

There is plenty of strong evidence that shows adding additional road capacity increases overall traffic. I'm not sure that adding ways to move cars around faster wouldn't have the same impact, versus a train.

> Cities like LA will become denser over time.

If the boring company solves issues with personal travel then cities like LS will become less dense. There's a reason urban sprawl didn't exist before the car.

Exactly. Cycling in LA is suicide.

Solve this problem by actually building protected cycling infrastructure and you'll make cycling viable and increase the amount of cyclists.

Agreed this is exactly the line of inquiry needed Dave. The Boring Company while novel, does not seem to be a representative "first principles" approach Elon has taken with other problems, it's we have cars how do we move more of them faster. I lived in London 10 years and happily moved from home, work, social activity on trains and buses very easily and happily. It's either you move to it, or it moves to you, or change the game so you don't need to physically move to be effective/productive/social i.e. remote work, home delivery, VR socialising. The Boring tunnel network - tunnel network as a service? TNaaS would be great for an automated freight and home delivery network, kind of like the modern scaled up pneumatic tube delivery system https://www.youtube.com/watch?v=sd58w0CXQrM I can imagine Amazon scaling this up.

Freight would be a great case for tunnels, if you could find a way to make the freight companies (say, Amazon) pay to use it. There's a reason why Amazon is pushing drone delivery, and I bet it's because they think they can get the rights to use the skies for free.

Elon did mention the tunnels being used for hyper loop

>>* Reduce the density of cities (enabled by remote work or longer commutes with better internet access).

Nope. Denser cities are both more efficient and more walkable.

All those things you propose are controlled by individual companies or the government. Musk is only doing what he thinks he can to reduce traffic.

There's another obvious solution, wait a few years and the end of cheap oil will fix traffic. Then the countries that built themselves around roads, cars and cheap oil will face larger issues (mostly US and Australia IIANM).

The worst part is that this had been foreseen and warnings have been made but nothing is done to deal with it.

If you wait a few years you'll have electric cars that are independent of cheap oil. And there will still be traffic. Perhaps it will no longer be soul-destroying because you'll be able to watch a movie, take a nap or get work done on your PC in your self-driving car.

There will be no end to cheap oil in the next 50 years. As demand decreases due to electric cars we'll see nearly 30-40% of the use of crude oil going away. The world has absolutely massive reserves of crude.

"I feel like only somebody who lives in LA would make the "must" assertion and not think about all the other options..."

I live in San Francisco and I assert that: To solve the soul-destroying practice of driving from (north of golden gate bridge) to SFO, roads must go 3D (tunnel).

You may not be aware of this, but if you need to go to SFO from Marin (or anywhere north of the city) you need to drive through small residential neighborhoods, stopping at up to 12 stoplights. It's incredibly wasteful of time and gas and degrades the lives of everyone involved. You find yourself stopped in traffic on a four lane boulevard in front of a single family home with a yard. That's how you get to SFO.

San Francisco desperately needs a tunnel from the GGB to SFSU/ParkMerced.

Those avenues are already being pursued. He's pursuing one that is not. That's a good thing.

Not every avenue not actively pursued is a good one though, I think thats the question people are asking.

Reducing density of cities actually increases a lot of problems. It means you have to spend a lot more of your time traveling, which will make all these problems worse. LA is a fairly low density city and has terrible traffic problems. It reduces economic efficiency, too.

Additionally, public transport often interferes with regular road traffic, making the problem worse. The solution is to use an elevated train (Chicago) or subways. So now you're back at 3D.

And biking in a low-density city isn't a practical solution.

I think remote work and online shopping are developing perfectly well without Musk's help. And I think we need to increase the density of cities (at least, city centres and inner suburbs).

How do the sleds preclude developing public transport? Why wouldn't we see mini-vans pick people up from homes or community hubs and then use the tunnels to take an express route to the CBD? Or larger sleds that accommodate a bus or truck sized pod? If these HOV pods avoided a congestion charge, there would be an incentive to use them.

Obviously drivers and their cars will fill any space given to them, and cycling tunnels might be too expensive, but hopefully a change in traffic flow and parking availability would make room and safety for cycling above ground.

Imagine buses with good cycling storage so you could ride to the hub, board a bus, zip to the CBD, alight and ride the last few kilometres to your destination.

Entrenched interests will fight it for a time, but it wouldn't surprise me if these guys could make it happen.

Your solutions are proportional reductions, a % reduction in the number of drivers. The problem of traffic rises with the ~2nd power of population because not only are there more people, there are more intersections.

Intersections can only be solved with 3d roads, by eliminating overlaps. The bigger the city, the more artery roads you need with uninterrupted flow, and they eventually choke each other. Build tunnels and you can have point-to-point connections without choking off local flow.

Reducing the number of drivers can't fully solve gridlock because at some point you have to hit a long light when you try to move from a high flow to low flow area. The only way to avoid that is with onramps and elevated freeways, but you can't build enough of those.

Public transport is at least an order of magnitude more efficient: http://p5.focus.de/img/fotos/origs3844236/5854568718-w630-h2... (note that car sizes have increased significantly since then)

Every point you brought forward is also true for subways, but it's again at least an order of magnitude more space-efficient than sending cars through tunnels.

Then think of this as a first-class and/or freight subway, I suppose. An extension of public transport to a new sector.

Reduced density of cities leads to longer distances and higher transportation needs, and less than ideal utilization of public transport. So that's counter-productive.

You can also fly. Skies are more 3D than digging and easier to access -- the problem with digging is that many people live and work and drive right above where you dig. At some point the holes could cause collapses. There's also water mains and other hazards and obstacles. Sounds dangerous.

> You can also fly. Skies are more 3D than digging and easier to access

And also a huge waste of energy on an ongoing basis. An aircraft has to continuously expend energy on fighting the gravity.

> the problem with digging is that many people live and work and drive right above where you dig.

The FAQ addresses that by noting that below ~2 tunnels height, people wouldn't even notice.

> You can also fly. Skies are more 3D than digging and easier to access

Easier, yes. Cheaper, no.

> At some point the holes could cause collapses.

The risk is extremely low, and car accidents have caused a vastly greater number of deaths than any other form of transportation.

> There's also water mains and other hazards and obstacles.

Pretty sure there were some pretty massive hazards with flying too.

> Sounds dangerous.

Which a lot of people said about flying as well. And it's vastly safer than a car.

I mean, it's also art. I would want it in my city just for that pissing-contest factor of 'hey, look at this cool shit we've got'. We deserve to make our cities beautiful and to build monuments to be proud of.


Darn those socialist Wall Street bankers and their well functioning New York subway!

why is one superior to the other in your opinion? If it solves the problem, it solves the problem

Is socialism the new communism? I once saw a socialist on the street didn't eat my children.

My exact first thought also... Closed the link after that :)

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact