- 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]
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.
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.
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.
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.
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.
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".
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").
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).
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.
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.
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.
> 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.
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.
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.
> 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.
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.
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.
> 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.
> 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.
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.
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.
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).
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 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.
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.
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.
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.)
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.
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.
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.
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.
>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.
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.
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?
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.
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).
> 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)
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.
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.
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.
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.
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?
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.
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.)
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.
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).
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.
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.
"- 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.
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.
- 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