Tunnels are our Transportation Future

Tunnels full of low-occupancy cars as a commuter alternative? I don't see much of anything in here about accidents/safety/emergency response. All of those things seem much harder in a "bunch of Model 3s in a tunnel doing point-to-point travel" world than in a Subway world, while also more likely to be needed, because you've got so many more vehicles sharing the space. Seems like a very important not-considered expense.

"The cost of loop stations is so cheap that you can place them next to any number of desirable locations."

This also feels wildly handwavey. You need a LOT of them if you want this to be a viable point to point network vs just a higher-risk way to build a subway. With individual vehicles going to individual stations at user request, too, we seem to have brought in "full autonomous driving" as a prereq.

It's tiring seeing so many people imagining solutions to transport that look like "Cars, but...". Cars are large and cause congestion, even if you make them autonomous. They need to be stored when not in use, which requires turning over more and more inner city land to vehicle use. And it becomes a self fulfilling prophecy: the more space you allocate to large carparks and multilane roads, the more spread out your city becomes and the any alternatives become less viable.

But instead this subject got 1 tiny paragraph near the end, in which this viewpoint "a form of degrowth".

"We can build more batteries, more cars, and more tunnels. And humans will be better off for it."

Honestly I just disagree with this take so much... I'm very far from a strident environmentalist but it should be obvious that this isn't the way forward.

Dedicated bus lanes are our transportation future. The capital expense and engineering are minimal (but not nothing), the capacity improvement is vast, and route to zero emissions clear (electric buses).

Taking the bus on a dedicated lane is a thing of beauty.

I don't think the "right of way" for tunnels is as simple and easy as the author claims. Many land rights include the soil beneath the land. While tunnels could be built below existing Federal and State owned land, many of the problems outlined for railroads by the author would happen again with acquiring the land required for tunnels.

Many of the other points in the article seem glossed over and error prone as well (e.g., simplifying the comparison between trains and trucks efficiencies to a rolling resistance coefficient and ignoring the discrepancies in weight of the vehicle an all other efficiency factors).

One of the things I wish we had done in earnest was focus on tunneling more for the last century - specifically for power infra-distribution.

If we had put the effort into trenching/tunneling for power dist - we would have saved quite a lot on fires and problems caused by downed powerlines. Fires, etc...

Further, power lines are FN Ugly.

We could have had specialized machines that dig a trench, lay/build conduit/tunnel hosings and then them up at the same time.

Also, if you look at how well Singapore has done in building 'down' -- they have massive underground causeways, malls etc - and its a shame that we are too shortsighted in our cities to give up such a HUGE % of the wonderful surface of the earth for things like cars and power distribution.

Every single building built should have underground parking and access. Cars, in dense urban environments should be relegated to subterranean transit only.

If there is a tunnel that moves a lot of vehicles quickly then that will generate problems at the entrance where vehicles line up to enter and at the end where vehicles exit. This may work out, but it is likely that all tunnel interfaces will, like bridges, require a complex array of interfaces to surface roadways. That adds a lot of expense and takes up a large amount of space, but there is no other way to make fast tunnels actually work to anywhere near their capacity. This implies that making fast tunnels work involves much more than the fast tunnels alone.

I like the part of this Tesla fan fic where the author says to, just build the tunnel the size of the car no bigger.

I guess bulldozers will be the preferred first responder vehicle then.

"Source: energy.gov"? Are you trying to keep readers from checking your work? Use hyperlinks.

Okay, the Loop proposal is absolutely bonkers, so let's go over why their "benefits" aren't so:

> Make the tunnel smaller.

The actual project costs of tunnel bores for the sizes of subway tunnels run closer to linear in diameter, not quadratic as you might imagine. A lot, indeed most of them, of tunneling costs aren't about the volume of fill you're extracting.

Furthermore, there's a massive cost to making them smaller: you're now limiting the interoperability of tunnels with other infrastructure. It becomes bottlenecks that requires things like unloading cargo in a warehouse and reloading them onto different infrastructure, or suffering reduced throughput on the existing infrastructure because you don't have as much capacity in the existing infrastructure. In the US, the freight trains have basically standardized on Plate H double-stacked cargo for all their plans, and any new freight mainline will have to support that anyways.

> Use above-ground stations.

Comparing with NYC 2nd Avenue Subway is somewhat disingenuous, because this is literally the most expensive subway in the world for construction costs. And there's several reasons for this, but they can largely be summarized as "the MTA is utterly incompetent at any form of cost control and nobody, not even the political overseers, cares two whits about holding them to task for their incompetence."

We actually know how to build subways cheaply. One of the great ways to cheapen their costs is to switch to cut-and-cover for construction, especially for stations which already have to be near the surface. Of course, cut-and-cover is incredibly disruptive, but because the stations still need access to the surface anyways, you end up with much of the disruption for longer periods anyways (because you need to move materials into and out of the underground construction area, so surface access is needed throughout construction).

But this also brings up another point: vertical circulation (moving people vertically). Vertical circulation is extremely challenging to do at high volume; it's one of the biggest bottlenecks in large passenger stations today. The proposed Loop tunnels would have to be underneath existing infrastructure--in NYC, the 7 is at 60 feet below ground--and now you have to somehow get that stuff to the surface expeditiously. A car elevator? That's going to handle about one car a minute. Or you can do ramps, at say 4% grade--that requires 1500 feet of horizontal displacement. Those ramps start eating up a lot of space quickly, and you're supposed to be doing cost stations by eliminating underground infrastructure.

> Use existing electric cars as vehicles instead of specialized train rolling stock.

What a horrible idea. The capacity of a free-flowing highway lane is roughly 2,000 cars per hour, and cars are not particularly easy to get lots of people in and out of them quickly. The typical capacity of a subway line is about 24 trains per hour, with each train able to carry roughly 1,000 people or so. If you plan your subway system well (which means having limited branching, so systems like DC's and NYC's are horribly, horribly screwed), you can push that up to Moscow's 45 trains per hour. Do the math as to how many people that can carry.

Operating costs of subways are likely to be much cheaper than Loop because there's fewer moving parts. And steel-on-steel is more efficient to move on than rubber-on-pavement.

And... I could keep going on tearing down the information here, but it's really low-quality. It's based on hopes and promises of what Musk says Loop could develop, with the convenient fact that it doesn't have any demonstrations of its actual capacity (since COVID-19 means that there's not really any demand for the Las Vegas Convention Center to stress-test it). But the technologies that it is most similar (Personal Rapid Transit) that have been developed and deployed in practice haven't lived up to its hype in the past. Why should we expect this new gadgetbahn to break the model of all the previous ones?

What's up with the timestamps in this thread? The submission is from the 3rd, but shows as "3 hours ago" and comments from days ago show as "2 hours ago"? https://news.ycombinator.com/item?id=28079363

My favourite (physics) teacher in high school once told us that "you can get anywhere on this planet in 44 minutes".

The caveat being that you need to drill straight through the earth to get there and jump inside.

Is it plausible to build a tunnel from China to the US through the ocean? Just a wild idea.

I guess I am unsurprised that this started out as an interesting read and then evolved into a full-on advertisement for Elon Musk companies.

When mankind started burning Gasoline they never contemplated that burning fossil fuels would damage the atmosphere and lead to runaway warming ...

It's the law of UNINTENDED consequences.

This seems like it could be even WORSE. I fear damage to the earth in unknown ways. Let's NOT make more tunnels ...

I work in a related industry. The article makes good points about the cost of tunneling and I think the boring company has some great ideas.

That said: * It's incorrect to think that there's nothing underground and this space is empty especially in urban areas. In Manhattan it's extremely difficult to find locations for new tunnels with the existing subway system, buildings, water supply, storm drains, power, things that aren't even on a map. Yes you could go deeper and deeper at great expense, but you still at some point need to tunnel to the surface.

* The proposal is to start the tunnel from the surface instead of from an open pit. Why are open pits needed for projects like the Purple Line in LA? Because even getting that pit built and opened is a major project, and you simply can't start it a thousand feet to the east, north, south, or west. The idea of not drilling in a pit is great if you can do it, but you can't ignore the advantages of drilling in a pit.

* Tunneling with a surface level entrance needed for cars will take more above ground infrastructure than a subway entrance. Once more, you'll need to allow cars to exit, so this will be repeated all along the tunnel. Subway stations are expensive, but the alternative is dismantling skyscrapers. It could be argued that all roads should be moved underground, Boston big-dig style, to free up space, but if you do that, you're spending lots of money on the surface as well.

* Tunnels need to stay dry and they can't make extreme angles and turns.

* Tunnels need to allow for evacuation and ventilation for the possibility of a fire. You can't get away from this with EVs.

* The "only" advantage of trains is not their low rolling resistance. The air resistance per passenger is also obviously much lower. You also reduce the amount of air and space between vehicles which increases your passenger capacity in terms of passengers per hour that can be carried in your tunnel during rush hour. Contrary to popular belief the space between cars cannot go away with FSD - the cars still need a safety margin to provide a safe braking distance from the car ahead. * In terms of safety, trains are much safer than automobiles per passenger mile traveled. It hardly even shows up in 2019 and they're only getting safer. https://injuryfacts.nsc.org/home-and-community/safety-topics...

* Trains have many downsides, but they're mostly related to being constrained to a fixed infrastructure. By putting cars in a tunnel you get many of the same downsides - freedom to change route, reverse, skip locations, avoid obstacles, etc.

In terms of future far-out infrastructure, I'd argue that "flying cars"/VTOL are a more likely solution that tunnels everywhere full of automobiles.