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It seems like all the discussion of vactrains is about transporting people.

But what about a smaller-diameter vactrain that could shuttle cargo around the world at thousands of mph? You could have a Chinese meal cooked in China and eat it in Europe while it's still hot.

A concern with vactrains is safety; if the vacuum is compromised, whatever's inside is destroyed as it's moving at such huge speeds. With cargo this would be less tragic.

Is there some reason not to do that? I can find very little discussion of it even from the proponents of building vactrains.

A disadvantage: loading and unloading would be quite a task if the packages are small (I'm thinking shoebox-sized), but if you have the tech for a vactrain you have the tech for a basic robot arm.

Smaller diameter tubes would, I think, be easier to build, although perhaps there's some engineering reason they'd be harder?

Thanks worldbuilders.

PS: I found a project called 'Pipenet': https://www.pipenet.info/sito_e/index_e.htm , https://web.archive.org/web/20210505172003/https://sifted.eu/articles/italy-deeptech-pipenet/

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    $\begingroup$ Pneumatic post, also known as capsule pipelines. In 1934 Paris has 427 kilometers (265 miles) of pneumatic pipes in service, connecting 130 offices. (And that doesn't include the physically separate confidential network of pneumatic tubes used by the government, the parliament, the senate and so on.) The public system was operated until 1984; the governmental system closed down in 2004. $\endgroup$
    – AlexP
    Sep 11, 2021 at 13:59
  • $\begingroup$ Related. $\endgroup$ Sep 11, 2021 at 14:20
  • $\begingroup$ If your cargo was time sensitive and you were willing to pay a huge premium for "pseudo-immediate" delivery then I think yes, but for most cargo, trains and boats while slow can carry thousands of tons. A freight train can move a ton of cargo 500 miles on a single gallon of fuel. $\endgroup$
    – JonSG
    Sep 11, 2021 at 14:21
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    $\begingroup$ You've stumbled upon the "Hyperloop Argument", which is rather vicious and has no right answer (yet). Many industry-leading experts say evacuated tube trains are nonsense and will never make sense, while many other industry-leading experts say that evacuated tube systems are the future of transportation. As a worldbuilder, this makes your job easy. Just agree with the experts that are proponents of the system, and you've got your answer. $\endgroup$
    – Dragongeek
    Sep 11, 2021 at 16:38

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It's been tried with High Speed Rail.

Many other HSR systems have looked into small-package freight, but none have found it worthwhile to implement.

Also, remember that cargo handling cost is an important component of total transport cost. That's one reason containerization is popular: It reduces handling costs. However, it's unlikely that --for example-- a hot dinner can be conveniently bundled/unbundled in a large container, so expect fairly high handling costs.

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There are all kinds of problems with high-speed stuff, km's per second, but if we skip all that, and focus on positive aspects - then sure it is a great stuff.

It isn't necessarily easy to build. Or rational to do so for china food, or <any other country you name it> food as it easier cheaper to replicate, with 100% authenticity - ingredients and including native cook, etc.

  • I mean if you imagine it for such things which require 20min or less delivery and places where they have to be delivered are in all corners of the world - forget it. Wait for teleporters and universal replicators. Too many problems, a list, but not the point of this answer.

As a point to point aka city to city transportation - those things can be quite good. And sure superior speed-wise to anything else, and sure that can be used to slash delivery time, or putting production facilities in unusual places, or storage systems it gives some valuable opportunities and despite being more on side point to point transport system it adds some flexibility to where and what we build, how do we use land, or sea (as an example).

Energy efficiency is an important question, which I'm not ready to answer atm and it defines or influences on decision making about those things, but skipping all the technical problems to make it happen, there is at least one thing which I think can help, and do that much better than fast-food delivery.

Transferring energy is one of the potential use cases, energy in form of the kinetic energy of that 'train',

Assume 2km/s speed for that payload, it can be faster it can be slower, but let's see what 2km/s does and instead of shoebox pipe, let's take regular oil one 800mm and alike.

1000 kg mass with the speed of 2000 m/s has a kinetic energy of 2 GJ.

So, a powerplant of middle-big size can launch 1-2 tonne per second and work at 100% power.

  • there are links between countries, electricity grid, which is about that capacity 0.5-1.5 GW it counts as a significant thing.

Imagine water-dense payloads fill the whole pipe, which power it can transfer - it about 2000 GW - all industrial countries together do not produce that much power in form of electricity even at peak hours.

Imagine solar panels, which some people like that much, in the middle of the pacific ocean, with the area of Sahara, generating electricity. Such pipe could deliver their portion of energy to few regions for future redistribution. Instead of solar panels, it can be some rectennas and energy from space.

Or it can be some nuclear power plants or fusion power plants which are not liked in the EU - which are placed a significant distance from consumers in super stable regions, or in depths of mountains next to fissile material storages(whatever, not the point)

Oil delivery is quite slow, natural gas does not deliver that much power as this pipe can do.

But what is the max cargo capacity of such hyperloop pipe in terms of cargo and mass delivery, same average density?

1000t per second, 80'000'000 tonnes per day - in terms of bulk cargo delivery it is a beast. A cargo ship, like an ore carrier, spends a few month's 3-4-5 on the route, assuming each ship carries 250'000 tonnes - such pipe could replace 32'000 of such ships(or even more) - we probably do not have that many ships of such displacement total in the world.

So power or use cases of such pipe can be very impressive, and much more useful. Even if it is 1% of the maximum capacity(a cart each 200 m distance in between) it is still a lot.

It could be a network of connections between production clusters and storage sorting redistribution facilities, which handles raw materials, energy, and products covering and connecting places over the globe. Closest to your shoebox system, in a sense how it looks and feels, but it fixed points system - material internet. Due to required accelerations not necessarily every product is suitable to be transported there but industrial stuff will have no problems for most of it.

Energy efficiency calculation for such solution should include the fact of displacement of other means of transport stuff, infrastructure benefits(fewer roads, fewer airplanes, fewer ports, fewer ships, etc), replacement of power lines power long-distance, opportunities to place nuclear power plants in best places, etc - so it not just energy per tonne per km evaluation. But yes in the end it is energy per tonne per km vs energy not spend on other infrastructures and stuff.

Unfortunately, there are plenty of technological problems to address in making this thing, including a lot of digging - the thing won't like changes in elevation that much. Would there be a way to build them easily, despite elevations and stuff, and it to be sufficiently energy-efficient - the stuff would rock as an energy/cargo transportation system.

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  • $\begingroup$ Have you considered regenerative load braking? $\endgroup$
    – Monty Wild
    Feb 14, 2022 at 22:38
  • $\begingroup$ @MontyWild that is how energy is delivered, you need to de-accelerate payload at where the energy is used - so yes. $\endgroup$
    – MolbOrg
    Feb 19, 2022 at 4:59
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In short:

In most cases, speed isn't important enough to justify the price tag for the infrastructure and its operations, and at the same time last mile bottlenecks mean that to reach as many places as quickly as possible, the complexity and price tag of the network goes up.

As has been mentioned in some of the other comments and answers, long distance high capacity but very slow transportation has been excruciatingly optimized to move a lot of stuff as cheaply as possible. Even perishable items and their supply chains have been optimized to ensure that they are delivered in exactly their intended state (banana shipping is a great example). The operational costs are low per unit of cargo shipped.

Vactrains and other related technologies provide very high speeds in exchange for a very high capital cost and high maintenance and operational costs (keeping long segments of tube pressurized is not a simple task). For cargo that is not time sensitive, it makes no business sense to use a technology with such a high cost when alternatives exist, and so the only cargo that can be feasibly transported by Vactrain is cargo that needs to be delivered very quickly. Do keep in mind that most products can arrive days late - people usually don't need same day delivery and can wait a day or two at the very least.

And so only very few products can take full advantage of the speed of Vactrains, and they tend to be time sensitive to an extent where any other mode of transportation would be too slow. This in itself is too niche for most practical cargo applications to work (passenger transportation is generally the only practical application since time is money when people are involved).

But Vactrains are best at long distances. They require straight lines for infrastructure, and to get products to and from the Vactrain, additional infrastructure is required. This infrastructure, if built into the Vactrain network, has all of the costs of Vactrain while providing substantially less in return the farther you branch out - this is why you have a tiered network for passenger transport, for example, where high speed rail connects to local and regional transportation for the last mile instead of building more high speed rail. So the options now are to either build more Vactrain into less-used areas where there are diminishing returns on investment, or to use a slower mode for the last mile.

But speed was the most important factor. So the latter, which is most practical, loses much of its benefit.

As a result, unless a reliable system can be built with good integrations for last mile delivery (very expensive), Vactrain is not going to be of much use.


Oh, and a final note. Containers are pretty standardized as far as dimensions go. This sets minimum requirements on guideway tube size, radius of curvature in the ROW, and the like. A Vactrain built into an existing logistics network would be required to follow those standards, at whatever price point that entails.

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