Subway systems are absolutely useless unless the stations are spaced very close together and there are other means of transit from the station to where you want to go. There is no point taking the subway when you need to walk several miles from the station to your ultimate destination.
There are only a handful of cities in the United States dense enough for a useful subway plus local transit system to make sense. New York is one. Chicago is borderline. Los Angeles is far too spread out for such a system to work.
On the other hand, if I can turn my car into a subway train and then get out of the tunnel and drive to where I want to go, that's actually useful.
> It's not about capacity. It's about convenience. Subway systems are absolutely useless unless the stations are spaced very close together and there are other means of transit from the station to where you want to go
Sooo... How is Musks' solution different? It's absolutely useless unless you have entry and exit points spaced very close together and there are means of transit from the exit point to where you want to go. You basically create chokepoints at each of those entries and exits.
Why not do "the stations are spaced very close together and there are other means of transit from the station to where you want to go." Scooters and bikes are a great way to do the latter.
> Why not do "the stations are spaced very close together and there are other means of transit from the station to where you want to go." Scooters and bikes are a great way to do the latter.
No they are not. Scooters and bikes are a great way to arrive at your destination sweaty, and you are at great risk of being run over by cars.
Multi-modal transportation only works if your coworkers don't care what you smell like.
I won't take public transit unless it's more convenient than driving a car. Nor will most other sane people. Even in the countries with the best public transit, nobody uses it when it is more convenient to drive. It's wonderful for dense cities and it's worthless everywhere else. By "dense" I mean London, Paris, and Tokyo. Once you get even 10 miles outside the centers of those cities you will find that driving is better, and that's what people do.
Are we talking about elonholes outside of cities now? I thought we were talking about cities.
The scooters I'm talking about are electric so you won't sweat. e-bikes are also a thing and they are becoming more of a thing. Finally, I'm sorry you feel uncomfortable around people. Not everyone does and for the most part public transit smelling is a meme that doesn't square most of the time.
> No they are not. Scooters and bikes are a great way to arrive at your destination sweaty, and you are at great risk of being run over by cars.
> Multi-modal transportation only works if your coworkers don't care what you smell like.
This makes sense if we're talking _today_ in cities such as LA, however if you look at biking-friendly cities such as Amsterdam or Stockholm, it's not really the case at all.
I'd go so far as to say that, in my experience, biking to work is as common (or even more?) as driving to work in central Stockholm, and the sweat problem you're talking about is really non-existing.
Why not? If he can convince a government panel that he can give them some value for their money, then it makes sense to "shell out money" (very persuasive language there - I approve) to him.
It's not free money. He has to give some value back.
I'm not sure what you're purporting to show other than two people disagreeing with each other, without providing evidence... Sure, an individual subway car has "more capacity," but does a subway system have more capacity? For example, I rarely see BART trains come within five minutes of each other. A tunnel that allows cars within 10 seconds of each other could provide more capacity than a tunnel with higher-density trains spaced further apart. Average density across the tunnel system could be higher (aka more throughout) with autonomous vehicles even if individual transport units have lower density (SUVs instead of train cars).
Off the top of my head, here are issues train cars face with managing density that autonomous vehicles wouldn't face:
1. Needing to stop at stations where few people are getting on or off, meaning that trains behind you must be at least (MAX_SPEED * STOP_TIME) behind you. With cheap tunnel boring + AVs, you can quickly and cheaply build tunnel branches that skip exits, so individual cars need less space between them (you branch off to exit; no need for extra rails or switching technology, since it's built into the cars).
2. Entrance/exit from the train car: with trains, any jerk can run in as the doors are closing, preventing the train from leaving, backing up the trains behind you and leaving a huge gap with trains in front of you. With AVs, you're already in the car.
3. Trains have fairly long stopping distances, increasing the distance needed between trains for safe operation. Some quick Googling indicated that an 8-car passenger train traveling at 80mph can take over a mile to come to a complete stop — it's hard to imagine a car with such long braking distances. That puts a pretty hard lower bound on how densely you can pack an ordinary subway tunnel.
Maybe I'm totally wrong, but it would be more useful to give actual data and evidence than knee-jerk shutdowns. It's not obvious to me, a non-train-engineer (like many on this site!), that the dismissive tweet is particularly meaningful.
The equivalent of BART in Paris (RER) has 90 seconds intervals between trains in peak time - and thats the regional train system, not the metro. It carries 50k pax per hour in each direction - that would be a lot of cars, like eleven cars a second at 1.2 person occupancy.
You mention "cheap tunnel boring" - maybe that is the keystone of Musk's plan that will change the paradigm... With a little knowledge of tunnel boring I fail to see how to disrupt its crazy complexity, especially in urban environments whose density extends underground already: in my neighborhood (La Défense business district) a whole new station is being build wholly under existing construction and interconnected to existing subterranean works, without any disruption - insanely good engineering and insanely expensive.
One of Elon Musk's ideas is that underground you can have a three dimensional system of tunnels and that this can help solve some of the capacity problems.
As dense and as cheap as Musk's technological vision becomes, a question remains: why carry a car at all instead of carrynig people ? Why carry mostly dead weight ? The denser the network, the more acute that question - if Musk's vision is an ubiquitous three-dimensional underground transport mesh, then why does it seem to conscientiously avoid being a public transportation system ? Does Musk believe that saturating the city with autonomous vehicles that use tunnels as network backbone can be more efficient than heavy public transportation networks ?
Peak headtimes on BART are a train every 2-3 minutes, with trains carrying up to 1400 people (let's call it 1000 for the sake of argument). So at the low end, that's around 20,000 people an hour. If you had cars with a headway of 5 seconds then that's 1200 cars an hour, so you'd need an average occupancy of over 16 people per car. That's unrealistic, so yes, a subway tunnel has more capacity.
That's assuming there's only one tunnel. As the article mentions the point is to dramatically reduce the cost to bore tunnels, so you can bore more of them.
If you could bore 4x the tunnels, you'd need a capacity of 4 people per car to match peak BART. And... hey, that describes pretty much every car in existence. But using the BART comparison: recent estimates [1] put each additional mile of BART track at over $1 billion. So if it really costs $10MM/mile for the Boring Co, you could bore 32x the tunnels and beat BART capacity by a factor of two assuming even single occupancy vehicles, at about a third of the cost.
cf London Underground - Central Line does ~260M journeys a year which is ~40k/hour assuming an 18 hour day. (I suspect peak times will be ~50% higher than that average.)
Even the Waterloo & City Line, the most unloved of all lines, manages 3.5k/hr over 260 days (16M/year, 5 day week).
> Sure, an individual subway car has "more capacity," but does a subway system have more capacity? For example, I rarely see BART trains come within five minutes of each other.
The BART is a particularly poor example. There are _tram_ systems (ie partially-segregated rail) which do better than once every five minutes.
Point to point transport in most cities is not at all a solved problem.
While this was demonstrated with a SUV there’s no reason why this can’t be used for a larger van carrying 6-12 people and tied to a carpool service. 12 people hurtling down this each second is pretty decent capacity, especially multiplied by many tunnels that do an even better job at getting people to the last mile.
>There is no universe where an SUV holding 4 people is more space efficient than a Skytrain car.
Except universes where a train doesn't pick you up at your house, drive you to the front door at work, take you to your kid's school after work, then take you to drop the kid off at karate practice, then take you directly to the grocery, then back to karate practice, then home but allowing you rapidly move your vehicle through a congested city thereby reducing surface congestion making overall travel conditions more efficient and reducing the need for car parks at public transportation stop for people that live in suburbs.
75 seconds is really, really long. Cars on a highway don't leave 75 seconds in between each other; if a cutting-edge train does, that starts to imply that density issues do exist for subway systems.
And how expensive was it to build the train? If you can build 3x the tunnels for AVs as you can train tunnels and trains for the same price, actual throughput dollar-for-dollar in infra spend would be much better with Boring Co tunnels.
Update with data: it cost $2 billion to build 50 miles of Skytrain. Apparently this prototype Boring Co tunnel cost $10 million per mile. That's a 4x cost advantage for Boring Co mile-for-mile, and I imagine they'll try to strengthen that advantage even further; after all, that's their whole company's purpose: cheap, efficient boring.
Right, but 15 SUVs 5s apart carry 105 people, and if they can actually travel at an average 150mph, that's faster than the average speed of Skytrain's fastest line by another 3x — so, now we're looking at 315 people moved through the space at the same time.
Factor in cost advantages of the tunnel — 4x cheaper mile-for-mile for the prototype, it seems like? — and the same dollars spent on Boring Co tunnels could actually move a lot more people than Skytrain: you can build 4x the tunnels, moving nearly 1300 people instead of 500.
Even if SUVs can only match the fastest average Skytrain line (50mph), that's still fairly competitive even at the current cost per mile of a Boring Co tunnel. Assuming they can bring cost down further (which is the goal of the company), they could still end up beating trains in terms of people moved per dollar spent.
Listen, I'm not saying it'll happen. But the dismissiveness here reminds me of the "Model 3 will never cost less to build than the price to sell it!!!!!" or "Tesla will never make more than 1000 cars per week!!!" or cash crunch or etc hysteria. I guess Elon attracts that by constantly missing deadlines, but he often still delivers; he just delivers a year or so late.
Despite your pretend block quote, that isn't a direct quote from me (you're taking quotes from someone else in the thread and splicing them into my post, using your made-up version as a strawman). I said 5s apart, which is over 1000ft of spacing — nearly a quarter of a mile, plenty of room for braking — at 150mph; the 15 SUVs is because 75/5 = 15, and we're comparing it to a train system with mandatory minimum 75s gaps.
This plan is like when a city widens a highway but doesn't touch other parts of the road network? What happens? It just moves the choke point somewhere else in the network.
Agreed 1s gaps are too tiny — seems unsafe and that'd be a lot of elevator traffic. 5s seems doable though: assuming 5s gaps, you need an elevator system capable of moving one car every 5s, and then the tunnel is optimally saturated. That doesn't seem insurmountably hard: two elevators that take 10s each to go from surface to tunnel would be enough, along with a bit of on-ramp tunnel to allow cars to accelerate to speed before merging. Throw in a third elevator or a fourth for redundancy while you're at it because elevators are way cheaper than a mile of tunnel, and seems doable.
You're assuming you can get cars into the elevators at 5s intervals.
Almost all assumtions in the discussion start directly in the tunnel, and sometimes at the elevator. Almost no one thinks about: how will cars get into that thing from the road, how the cars will get out of that thing onto the road.
It's probably just me but I really wouldn't get into anything that was going to be travelling 150mph at 1s intervals. All you need is a tire to go (or something loose on the floor or a dead battery or ...) and you've got not only a huge twisted lump of metal and body parts to untangle, you've almost certainly ruined your tunnel.
You're comparing a prototype with a real life operating system that was built to be um, you know safe and good, unlike what has been shown with this prototype.
The fact is that a 500 capacity train running at 75-100s headways destroys this system capacitywise.
Musk has a long, long way to go before he shows that this idea of his is better than the 1986 era technology at the core of Vancouver's system.
> The fact is that a 500 capacity train running at 75-100s headways destroys this system capacitywise.
This is like that linked tweet: all assertion, no data. What are you using to estimate the theoretical throughput of a Boring Co tunnel system vs Skytrain? Let's debate that. Right now it's all just thin air.
Assumptions I'm willing to believe, and thus make me interested in this prototype's viability:
1. Cars need less space in between them. 5-10s gaps seem more than reasonable based on highway driving. This seems especially true since these are operated autonomously in highly controlled environments, meaning we might need even less distance between cars than free-wheeling, human-operated highway driving.
2. Most train stops are useless for most people — maybe 3x stops per ride on average? Having only one stop per ride would dramatically improve average speed, since a smaller percentage would be spent slowing down, speeding up, or waiting at a station.
3. Smaller tunnels are cheaper to dig, meaning dollar-for-dollar you can build more of them to make up any remaining capacity difference.
Well even if it weren't higher capacity, it has other advantages -- no parking/leaving the car, potentially no ticket gates or waiting for a train... etc.
Trying new ideas isn't a waste of everyone's time, it's research.
>and if it doesn't work out, it can always be converted to rail
Or worst case likely office, manufacturing or even residential space, I mean... that's a LOT of square footage that just got created in an area with very expensive real estate.
12ft diameter gives you at least 8ft of internal space x a mile. Japan for example has 100sqft apartments. I've worked in an office, in Indianapolis, that wasn't even 8ft across and there were 20ish of us with desks against the wall so little space you had to slide all the way in for someone to walk down the aisle.
You could cut a channel down the center for plumbing and electrical conduit, probably only have a foot of clearance on one side, then have a walkway down the other side and make quite a bit of comparable office space.
Most THOW, tiny homes on wheels, are less than 8.5 feet wide to remain legal trailer width in most states so you've already got people living like that in the US. Here you could cut elevator shafts every eighth of a mile and just make the freight elevators. Say after fire suppression, pumps etc, you only have 4500ft of length to rent/lease/sell you could have 200+ small offices/apartments/artists spaces/climate controlled storage units.
I mean a Type IXC submarine (like U-505 at the Museum of Science and Industry in Chicago) had a pressure hull beam (width) of 14ft 5in and you still had material between the crewed area and that hull. Having been in U-505, and being 6'1 300lbs, even with a full tour I found it had plenty of room to move about and would have happily lived on it. Especially if it didn't have pipes/gauges/equipment/cabinets/cots etc hanging off the walls. Those things ran with crews of 50-60 people for months at a time, small offices or flats for 1-2 people would sell quite well I'm sure. Hell, I've been in escape rooms that weren't wide enough for me to lay down in.
oh i don't doubt that it can fit. but i can't imagine it being popular.
japan has small apartments out of necessity. not because they like living in small spaces.
add that working or living under artificial light is not exactly healthy. this idea strikes me as something for an emergency shelter, backup workspace, but not for normal operation/living.
right, it might not work for a regular sized train, but if it can fit a car, it can fit rails and a custom designed rail carriage with the same advantages of a regular train.
it might not even need regular rails. there are trains that work with rubber wheels (paris subway had that for decades already), so it would really just be fancy busses with guide-rails.
EDIT: pretty much the same idea is mentioned by several others in this discussion, so it seems not to be to far fetched.
of course, given the popularity of public transportation in LA, it makes sense that they are going for the ability for people to use one vehicle from their home all the way to their destination. i just hope they focus on actually getting the most use out of the tunnels, even if their initial vision doesn't work out the way they intend.
IIRC the main heat source is the breaking of the trains combined with the high frequency of them. I suspect that using many cars will still release a lot of heat into the tunnels.
The trains in the narrow tunnels push air around, so recent stuff like full height platform screen doors help improve conditions (allowing platforms to be air conditioned without having to air condition the tunnels)
Sure it’s not density of subway but more tunnels will partially offset lower capacity. This is about lowering tunnel & ‘station’ construction by ~2 orders of magnitude. There’s also lots of room underground to build vs surface, so little constraint there.
Lowering cost is Elon’s demonstrated strength (SpaceX rockets and Tesla batteries), so gotta factor that in. Small tunnels cost way less than subway tunnels, not factoring in improvements in boring ops. It’s all about shaving off 2x here and 5x there across the whole system to make it cheap enough to get benefits.
Lower cost let’s you open up new routes to lower density areas. Means cars can get off the road from those areas which would otherwise contribute to traffic.
This is like going from mainframes to personal computers - enabled by lower cost, more people can have access.
LA metro has a tough job in their hands with handling their traffic and is likely behind this. It’s not trying to be or marketed as a direct substitution for subway, it’s another option that happens to compare favorably but be implemented in a different way and by different parties.
Alternative comparison is to freeway which has 1 car every 2 seconds, and this claims 1 car a second on main path.
> There’s also lots of room underground to build vs surface, so little constraint there.
There are lots of constraints building underground. Because on ground level the buildings have been built with certain assumptions about the ground regarding the construction structure. When the underground now changes, then either the ground will collapse or the underground tunnels have to been build statically according to those requirements. That is the hard work of tunneling.
Also maintaining the tunnels regarding ground water levels is hard. Changing ground water levels also has impact in the statics of the building on the ground.
There are much more things to consider building and maintaining underground.
Agree I was being a bit dismissive on that for expediency sake. It’s not without issues, but it represents the best available location to build. I imagine small tunnels can partially mitigate these issues.
I don't understand this. HN is better than most forums but seriously, the level at which people's minds online turn off for Elon is staggeringly confusing.
I thought it was obvious this would quickly become an expensive express option. It's not going to fix traffic for the masses, it's going to fix it for the rich.
As with literally every other technology. It starts out as something for rich people and if it proves useful demand will grow, price will fall. Cars were a luxury once.
The point is to make tunnel boring cheap and to build an system of dynamic individual or group transport.
Rejecting the system because rich people use it first is socialist logic and has no place specially if its not done with government money.
https://twitter.com/elonmusk/status/1075230308545454080
How can this man honestly think this sort of system could be higher capacity than a subway?