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Comment by Pxtl | Hacker News Reader

> There is simply no future in which passenger rail competes with air travel in the US. Even in circumstances where the distances are not too great, and the political and bureaucratic hurdles are.

This ignores the existence of climate change. Air travel is not sustainable and air travel is least amenable to conversion to hydrogen or electric.

As you mention, the chief barriers to HSR in North America are political and bureaucratic, not practical. What's missing, then, is the political will to do hard things.

Governments used to be able to do things, when the situation demanded it.

http://www.thepaincomics.com/weekly080730.htm

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Aviation accounts for 2.5% of global CO2 emissions. It's not low-hanging fruit.

https://ourworldindata.org/co2-emissions-from-aviation

> Aviation accounts for 2.5% of global CO2 emissions. It's not low-hanging fruit.

Aviation accounts for 9% [1] of US transportation co2 emissions (and as they're emitted at high altitude, impact is likely more like 13-14%)

[1] https://www.epa.gov/greenvehicles/fast-facts-transportation-...

All sources of CO2 emissions look small when broken down to that level of granularity.

From the source cited, here is a breakdown per industry:

https://ourworldindata.org/ghg-emissions-by-sector

Energy usage for industry is 24%

Road travel is 11%

It seems aviation’s 2% is not the low hanging fruit.

But passenger road traffic is only 7%. The rest is freight which requires a completely different solution.

There is no low hanging fruit. We need to address every sector. No individual solution is going to cut more than a few percent of total carbon emissions.

24% industrial use is in my mind.

A buddy of mine worked for a startup a few years ago that promised to go into large plants and do some trickery with the harmonic losses with the very large AC motors in a lot of the big equipment. Apparently there is a lot of losses in such things. They would install equipment to improve the situation in exchange for a portion of the energy savings over time, which was considerable.

Except that also breaks down into 7% iron/steel, 3.6% chemical and oil, 1% food and tobacco and many other small categories.

Is the same solution that cuts down on carbon emissions in making steel going to cut emissions when making fertilizer?

Yes, because all those plants have big AC motors driving the machinery. Any place where there is a big AC motor can benefit from this. That means most of the applications you can think of.

And trains can't replace transoceanic flights. I don't know what percentage, but not all of that 2.5% can be eliminated with trains.

A society that takes climate change seriously will replace international air travel with passenger ships featuring high-speed satellite internet and spacious work areas. Little-known fact, ocean travel is 3x more energy-efficient than even rail.

People value their time. There is a reason we replaced modes of travel that require days or weeks of travel time with modes of travel that only require hours. Society and culture has been heavily optimized around the fact that it doesn't take weeks to get to where you are trying to go. The world is global and distances are long.

Few people want to be stuck on a passenger ship for weeks at a time, their objective is not to be sitting on a ship. It would make international travel completely infeasible for all but a minority. No one would be able to do simple things like visit family if it required a month or more of round-trip transit time.

I'm not an idiot, I know why people travel by jet aircraft. These luxuries are irrelevant in the face of climate change.

Society has been organized around jet travel. It can be reorganized around the reality of international travel requiring large time investment.

Society is organized around individuals and groups working in mutual self interest. If you go against this principle to find your solution you risk backlash to your (perceived or real) tyranny.

Society is not organized around individuals and groups working in mutual self-interest. Society is organized around the interests of the wealthy. Indeed, only people who are quite well-off manage to take international flights. Immigrants I know are happy if they manage to travel back and meet their families once every 3-5 years.

These aren't luxuries, business and society is global now. Unwinding a century of globalization would impoverish many regions of the world. It isn't a mere inconvenience, it would be undoing a vast amount of economic development and progress. People aren't going to be receptive to sacrificing any hope of prosperity for them and theirs.

An argument of "but climate change" is tone deaf and not very compelling when it is you getting thrown under the bus for the Greater Good. Economic realities can't be ignored when they are inconvenient.

Unsurprising that someone who, from their bio, "splits their time between Seattle and London" is against this idea.

The economic effects of climate change will be more catastrophic than making it take longer to move internationally, something that very very few people actually have a need to do.

Nice non sequitur and evasion of an inconvenient point. I travel internationally because it is necessary, not because I particularly want to. Rather more business than you may imagine cannot be done remotely. Nonetheless, my carbon footprint is significantly lower than the average American.

Addressing climate change in anything more than a performative way will require massive increases in global industrialization, not less. Impactful eco-friendly infrastructure isn't going to build itself. Needlessly making this slower and more difficult than necessary just lends credence to the idea that climate change activists aren't serious about addressing the problem.

The promotion of non-serious solutions to climate change make it much more difficult to get by in from average people for supporting credible and substantive solutions. Which isn't helpful if the objective is to constructively address climate change.

It isn't a "non sequitur" to point out you're part of a very small class of people taking multiple international flights a year. That isn't what that term means! Anything you view as "necessary" is very unlikely to be so in the face of existential concerns. But of course, anything that derails your lifestyle just isn't serious.

There's no society on earth taking climate change as seriously as warranted if the worst projections are to be believed.

And there's no precedent for the level of global cooperation -- which would have to transcend nation-level political realities -- required for meaningful change.

I'm long on humanity. But not because I think we're all going to wake up and fix the climate in a coordinated manner.

I think you’d have better luck with zeppelins.

The trouble with zeppelins is that unloading is difficult. Every lb of weight removed from the Zeppelin is another lb of lift that has to be offset. So you have to do things like pump water into the zeppelin as people or cargo disembark. Ships also face this problem to an extent (unloaded ships are unstable) but they are sitting inside a functionally infinite pool of water they can pump in & out.

Zeppelins are tres tres romantique, though.

I thought you just tied the zeppelin down. Couldn’t you reduce the amount of helium in them?

Pumping helium in & out of a zeppelin would be even more complicated than pumping water.

Or you could load a heavier material for ballast, and gradually transform it into a lead zeppelin.

But seriously, why can’t you just tie the zeppelin down? Is there not any sort of cable material with enough tensile strength?

Hmmm, running some rough calculations the passenger load probably wouldn't exceed about 50 tons for 500 people. Which is very doable to do with a tether. So maybe you're right! Solar-powered passenger airships could be the future. It's cargo airships I'm thinking of that really have these drawbacks.

And for a cargo zeppelin, swapping out full shipping containers for weighted ballast shipping containers seems pretty easy. Though I seriously doubt cargo zeppelins make any sense at all.

The share of warming is higher than the pure emissions because of the aerosol effects and resulting heat trapping. Some estimates are twice as much.

I'm not arguing the point. We are far more able to tackle ground-vehicle emissions, home heating, and electrical generation.

But eventually air travel's time will come, and HSR is the only alternative that's on the table.

There are also carbon capture and sequestration and closed-loop hydrocarbon fuel production using carbon-neutral energy sources.

It’s completely false, unnecessary, and counterproductive to spread FUD about climate change requiring substantial reductions in quality of life. People are smart and resourceful enough to solve these problems.

Less travel is also on the table. We should do all of the above. A hefty carbon tax is the holistic instrument, but I'll take any/all paths.

> This ignores the existence of climate change. Air travel is not sustainable and air travel is least amenable to conversion to hydrogen or electric.

Which means you’d have to use hydrocarbon fuel. Which can be chemically produced from atmospheric CO2 and water if you have enough carbon-neutral energy. Or you could sequester an offsetting amount of CO2 if that would be more efficient.

In North America geography is the primary impediment to passenger rail of all stripes. High speed rail is even more at the mercy of physical reality.

Look at the article’s map. That empty distance between San Antonio and El Paso is nearly 900km of West Texas emptiness. There’s Del Rio and Van Horne as the biggest towns and Marfa as perhaps the most famous.

When last was San Antonio to El Paso an important trip for someone you know?

> climate change

Also peak oil, a largely forgotten issue. As fuels get more expensive, more efficient modes of travel will become cheaper relative to air.

Peak oil is “a largely forgotten issue” because it was a largely overblown issue to begin with. Fracking relieved the immediate supply pressure while reductions in demand will help matters even more.

Fuel shortages are unlikely to be a serious risk for centuries. Hydrocarbon reserves are measured in the trillions of barrels (in the US alone) and the different types are largely fungible at <$100 barrel inasmuch as you can convert them all into fuel.

We may greatly reduce hydrocarbon fuel usage but it won't be because we ran out in my lifetime.

Climate change doesn't make trains any better. What we need is Skytran: https://www.skytran.com/

How many times will people keep proposing PRT before they discover that it doesn't work?

PRT is incredibly new technology in an industry that is incredibly slow to innovate. Are you really calling PRT dead after 30 years of ideation and literally 1 medium scale project? Seems pretty premature to call it dead if you ask me.

What's PRT?

PRT is short for Personal Rapid Transit, and it's a form of transit that basically combines some sort of fixed-guideway-like system with small-capacity individually-routable pods instead of trains. As a result, it kind of ends up with the worst of both worlds: you have the infrastructure complexity (and cost) of a train with the throughput (or lack thereof) of single-occupant cars.

(Musk's Loop idea is basically another iteration of the PRT concept.)

You do not have the infrastructure complexity and cost of trains. Because vehicles are small (pounds instead of tons), guideways are literally an order of magnitude cheaper. You can build track for $5 million per mile instead of $50 or $100 million per mile. You can build a grid system instead of arterial lines. Guideway is light so can be off the grid and easily avoid dangerous intersections with roads and other ground pathways. A single skytran guideway has capacity of 14,400 per hour - more capacity than 7 lanes of freeway or [3 tracks of at-grade light rail](https://www.liveabout.com/passenger-capacity-of-transit-2798...) and 50% more than grade-separated light rail (which is rare).

Your thinking is out of date.

Morgantown PRT has 20-person capacity cars. That doesn't seem so inefficient. On the other hand, it only operates as a PRT during off-peak according to the wiki page - during peak hours, it's just a standard scheduled service like a train or bus.

That said, the Musk Loop type plans where the cabs/cars only carry 1-4 people - which seems similar to this SkyTran - is obviously inefficient and not really a realistic alternative to cars or mass transit systems.

> is obviously inefficient

You only think that because you haven't done the math. Its frustrating to hear people talk about how something is "obvious" when by "obvious" they just mean "I haven't actually put any thought into it.

A single Skytran track has more capacity than 7 lanes of freeway or 3 tracks of light rail. Does that sound "obviously" inefficient to you?

I call BS on that math immediately.

A lane of freeway can move about 1500-2000 people per hour in single-occupant vehicles. If you're moving 2k people/hour in 4-person cars on a fixed guideway, you need to have about 10 seconds between vehicles. That's about 8 seconds for a car to physically clear the switch, the switch to physically move to an alternative position, and then the trailing car to cross the space needed to come to a complete stop should the switch fail to actually work. If you claim 7× the capacity, you need to do all of that in a little more than a second.

So, yes I have "actually put any thought into it." I've put sufficient thought to recognize standard gadgetbahn claims with standard gadgetbahn levels of evidence backing them up, and thus I can respond with standard gadgetbahn criticisms.

Personal Rapid Transit: https://en.wikipedia.org/wiki/Personal_rapid_transit

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