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Comment by ProblemFactory | Hacker News Reader

Is technology really the slow and expensive part of boring tunnels? To me it has always seemed that tunnels are expensive because:

* Planning the traffic impact and how it interacts with other transport lanes, all the above-ground building work to make the tunnel useful,

* Emergency ventilation and escape routes, and all other infrastructure that goes into the hole,

* Avoiding any building foundation piles, unmapped tunnels, pipes and cables, re-planning and fixing them if you do hit them,

* In Europe at least, archeological surveys.

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Of course Musk understands that this problem is hard. That's why there are not already hundreds of tunnels under cities when it is the obvious solution to the current problem with our wheel based, point-to-point transportation system. He has the ability and funds to gather and inspire the best-of-the-best to maybe make real progress on this problem. Check out the one minute Boring Company promo video[1] for some preliminarily ideas for solving some of your above issues. 1. On street elevators to interface with tunnels. 2. Electric carts to eliminate combustion in the tunnels. Much less ventilation needed. 3. Once below a certain depth there are few things to avoid. See 1 for why this is might be possible. 4. See 3.

It is easy to speculate on why something might not work. Most of the universe consists of nothing (by volume) or a random assortment of very fast moving hydrogen and helium ions (by mass) (not sure where black holes fit in). Interesting things are rare. They are very complex systems that have built-up and evolved over time. If you want to try and build such a system, a good way is to look at the problem from a fundamental physics and economic view (first principles, as Musk would say) to see if it is possible. If it is, then start thinking about it seriously, gather like-minded people, and start building things. It's impossible to plan all the necessary steps before starting a journey that never been done before.

[1]https://www.youtube.com/watch?v=u5V_VzRrSBI

It may be time to legislate the concept of "tunnel space". This would be similar to air space. In the US a property owner doesn't control the air above their land (subject to details). Maybe Congress should declare the Earth below say 100' as not controlled by the land owner and allocated by some new agency, say the Federal Crust Administration.

Remove all of this from state, county, and municipal jurisdiction. Centralize the rules. Local government will still be controlling the portals where it must surface and interact with the surface world.

This will have to merge with mineral rights, but the intersection of mass transit and mining is minimal.

Every mining company will lobby against that. It's probably easier to do it with easements and eminent domain.

This concept already does exist, and is used by mining companies, so no they won't lobby against it. There are a lot of cities in Pennsylvania with coal mines a mile underneath them.

> This concept already does exist,

No, it doesn't. You are confusing the severability and frequent separate sale of mineral rights to a federalization of all subterranean property.

I believe they're hoping to mitigate 3 and 4 by going deeper than most things. But wouldn't that make 2, emergency escape routes, a lot more expensive?

How do you make a very long, very deep, narrow-diameter, elevator-accessed tunnel safe from fires and toxic gas releases? You can make it a vacuum but then what if you have to escape a vehicle? How does this thing not become a death trap in the event of a fire?

Fire is the number one cause of fatalities in tunnels (remember it's the smoke that kills). Tons of engineering and expense goes into trying to devise shelter and evacuation solutions.

You won't get fires if there is nothing that burns.

So... passengers can't wear clothing or bring any belongings with them that can burn?

Things you can take on a plane would probably be alright.

But you're accepting passengers and what they carry.

Wishful thinking. The video envisions Teslas driving directly into the tunnel system via elevators. That means arbitrary cargo and, moreover, Teslas have giant battery packs that can catch fire.

The Channel Tunnel is a good example of how it could be done safely. There are two tunnels for trains, and a third smaller tunnel in the middle for emergency use. In the event of a fire people can be (and have been - there have been a few fires) evacuated to the service tunnel, and then road vehicles are sent to collect them.

The Channel Tunnel is only 31.5 miles long vs 230 miles (driving) from New York to DC, but having an access shaft every 30 miles or so wouldn't be that bad.

I'm not sure how you'd deal with the vacuum issue though - I guess doors at regular intervals that can be sealed, so a section of the tunnel can be bought back to atmospheric pressure, and the emergency doors can be opened between the car-tunnel and tunnel-emergency tunnel.

That's precisely my point: with that approach they'd have to dig an parallel 230 mile tunnel just for emergency access. Plus cross passage escape tubes that you can get to on foot before you're overtaken by smoke or gases.

The Gotthard tunnel has them about every half mile, but the Boring Company will use smaller diameter tunnels where smoke and gas spread faster, so they'll probably need them more tightly spaced -- say, every quarter mile. And they'll use separate tunnels for each direction of traffic. So that's three tunnels plus 230 x 4 x 2 = 1,840 cross passage tubes.

This is all technically achievable, but the Boring Company's vision is all about cost.. building tunnels 10X cheaper. This is, I think, at least as great of a challenge as getting government approvals to dig very deep.

Planning the traffic impact

Solution: Do not connect the tunnel directly to the road network.

Emergency ventilation

Solution: Build a kind of infrastructure that only allows onboard backup as emergency ventilation.

Escape routes

Solution: Minimize escape shafts and provision emergency rescue vehicles capable of transporting an entire pod. Maximize reliability by exploiting the increased reliability of electric drivetrains and leveraging institutional knowledge from SpaceX and Tesla.

all other infrastructure that goes into the hole

Solution: Minimize "all other" which is not simply the hole.

Avoiding any building foundation piles,...archeological surveys

Solution: Go deep enough to avoid all of these.

Those problems are hard for a reason. XKCD puts it succinctly: https://xkcd.com/1831/

> Solution: Do not connect the tunnel directly to the road network.

Then how do people get there? Train? OK, then you have to plan how it interacts with the train network's traffic and schedules, duh.

At least that's easier than car traffic... OH WAIT! Train stations usually have parking, or even if they didn't, are in the middle of a city, not at the top of a tower in the himalayas. So even if you don't want them to, people can drive to near an entrance and park. There will be induced traffic, and there is no way to keep the two networks unrelated without making the tunnel network totally useless.

> Solution: Build a kind of infrastructure that only allows onboard backup as emergency ventilation.

FWIW This also means you have to ban internal combustion engines (which should be OK). Just to deal with ICE exhaust, the Holland tunnel replaces all the air inside it every 90 seconds.

> Solution: Minimize "all other" which is not simply the hole.

You don't even know what "all other" is, do you? I don't either, but this whole set of solutions is really borderline "Why don't they just make the whole plane out of the black box?" ignorant sounding.

> Solution: Go deep enough to avoid all of these.

And I'm as ignorant as you, but I remember reading somewhere that digging costs can be exponentialish as depth increases, for a bunch of reasons.

Then how do people get there? Train? OK, then you have to plan how it interacts with the train network's traffic and schedules, duh.

Your reasoning applies equally to airports. Congrats, you just "debunked" the airplane! (duh!)

So even if you don't want them to, people can drive to near an entrance and park. There will be induced traffic

This is vacuous. There will always be induced traffic for such a project. But the kind of planning required for the kind produced by an airport is materially different from the kind produced by an entirely new highway. Also, if your new "airport" requires the construction of a new road in the future, this isn't as big a short term barrier as those around an entirely new major highway, and will be borne by the local government.

FWIW This also means you have to ban internal combustion engines

FWIW, I'm glad you finally caught up with my actual idea!

You don't even know what "all other" is, do you?

That's not relevant at this level. I don't have to know all the details of building a road to know that not building a road and flying a cargo will avoid those expenses and incur different ones. What is your point, here?

(Here's a hint, when discussing major infrastructure, don't automatically ascribe to others straw man positions of zero cost! That's not exactly a "charitable" reading.)

And I'm as ignorant as you, but

...a little soft in the reasoning. If digging costs are exponential with depth, then this would be an interesting point. I'm not sure if I should really credit that. Well, I guess one would deserve credit for bringing that to attention. So your comment makes, charitably, a "half point."

> Your reasoning applies equally to airports.

That's not really in dispute.

> Congrats, you just "debunked" the airplane! (duh!)

If by “debunked the airplane” you mean “demonstrated the already widely-accepted fact that air travel only is effective with considerable attention to the surface transport connecting airports to the places people actually want to go to and from in the area serviced by the airport”, sure.

If by “debunked the airplane” you mean “demonstrated the already widely-accepted fact that air travel only is effective with considerable attention to the surface transport

Well, yes! Perhaps I shouldn't have used the click-baity, "Solved:" but those are my best guesses as to the strategies used to minimize the problems.

There is the small matter of geology, following have to be considered, for example:

-Rock type

-Groundwater flow

-Tectonic activity

You can have a whole career as a geotechnical engineer. There are genuine and difficult problems that require consideration if your tunnel isn't to collapse after a few years of use. I don't think these problems magically disappear with new technology or going deep enough.

I can't upvote your comment enough and I would add geology to that list.

#2 and 3 certainly sound like technology problems; eg #3 - would underground probes, small tunnelers, help survey the territory between point A and B?

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